If we believe not, he continueth faithful, he can not deny himself.

“Now the so-called gods of the Greeks, unworthy of the name, are faithful neither in their essence nor in their promises. They do not abide everywhere. The local deities come to nought in the course of time and undergo a natural dissolution.… But the God of all, being one really and indeed and true, is faithful, who is ever the same.… He is ever the same and unchanging, deceiving neither in his essence nor in his promise. As again says the apostle writing to the Thessalonians, "Faithful is he who calls you, who also will do it"; for in doing what he promises, he is faithful to his words. And he thus writes to the Hebrews as to the word's meaning "unchangeable": "If we believe not, yet he abides faithful; he cannot deny himself."”

“What then meaneth, "Can do nothing of Himself"? That He can do nothing in opposition to the Father, nothing alien from, nothing strange to Him, which is especially the assertion of One declaring an Equality and entire agreement. But wherefore said He not, that "He doeth nothing contrary," instead of, "He cannot do"? It was that from this again He might show the invariableness and exactness of the Equality, for the expression imputes not weakness to Him, but even shows His great power; since in another place Paul saith of the Father, "That by two immutable things in which it was impossible for God to lie" (Heb. vi. 18): and again, "If we deny Him - He abideth faithful," for "He cannot deny Himself." (2 Tim. ii. 12, 2 Tim. ii. 13.) And in truth this expression, "impossible," is not declaratory of weakness, but power, power unspeakable. For what He saith is of this kind, that "that Essence admitteth not such things as these." For just as when we also say, "it is impossible for God to do wrong," we do not impute to Him any weakness, but confess in Him an unutterable power; so when He also saith, "I can of Mine own Self do nothing," His meaning is, that "it is impossible, nature admits not, that I should do anything contrary to the Father."”

“The only thing the Almighty cannot do is what he does not will, in case anybody should consider it was very rash of me to say that the Almighty "cannot" do something. The blessed apostle said it too, "If we do not believe, he remains faithful, for he cannot deny himself." But it is because he does not wish to that he cannot do it, because he cannot even have the will to. Justice, after all, cannot have the will to do what is unjust, or wisdom will what is foolish, or truth will what is false.”

“Faith is that which is not a name only, nor is it even voice or speech; but it is that which sheweth itself by the true examination of the soul, and by the sure and certain stability of the thoughts, and it denieth not itself, but in this respect also it is to be compared with God, concerning Whom Paul saith, "He cannot deny Himself." Thus also is it with the faith which denieth not itself, which bringeth not doubt upon itself, upon which no suspicion falleth, and whose power fear reacheth not. Everything that it wisheth, it doeth, and whatsoever it seeketh is given unto it.”

“Above, the preparation for martyrdom was set forth; here the exhortation to it is set forth, and first he sets forth in advance the example of the reward; second, the example of martyrdom, at in which I labor; third, he shows the connection of the reward to martyrdom, at faithful is the saying. For the reward of the precious death of martyrdom is the glorious resurrection, the example of which preceded in Christ our head. And therefore he says be mindful, etc., as if to say: our Lord Jesus Christ — supply: keep him in mind against tribulations. Prov. 3:6: In all your ways think on him, and he will direct your steps. For there are many things to be thought about in him, but especially the resurrection. To this all things are ordered, and especially the whole state of the Christian religion. Rom. 10:9: If you confess with your mouth the Lord Jesus, and believe in your heart that God raised him from the dead, you will be saved. And note that he says raised up, because although the Father raised him, yet he also rose by his own power, and he is the first of those rising, 1 Cor. 15:20. But because he rose according to human nature, and died, of the seed of David. Rom. 1:3: who was made to him of the seed of David according to the flesh, et cetera. According to my Gospel, that is, preached by me. 1 Cor. 15:1: But I make known to you the Gospel which I preached to you. He who preaches the Gospel is a minister of the Gospel, just as he who baptizes is a minister of Baptism. Yet it cannot be said "my Baptism," but "my Gospel" can be said thus. And this is so because exhortation and solicitude contribute much. Then, when he says in which I labor, he shows himself as an example of martyrdom, and first its punishment; second its cause, at therefore all things. Now he shows three things to be in the punishment, namely bitterness, reproach, and constancy. Bitterness, when he says in which, namely in preaching the Gospel, or for which I labor, that is, I am afflicted, and this even unto bonds, because when he wrote this epistle, he was at Rome in bonds. Eph., last chapter: the ministry of the Gospel, for which I act as ambassador in a chain. Reproach as regards unbelievers, when he says as an evildoer. For Christians then were reputed the worst. Lc. 9: Blessed will you be when men hate you, and separate you, and reproach you, et cetera. Christ too was condemned, as an evildoer. Is. 53:12: and he was reputed with the wicked. But he shows constancy, when he says but the word of God, et cetera. For although the body is bound, yet the word of God is not bound, because preaching came from the will of the apostle, which is free, especially on account of the efficacy of charity, which fears nothing. Rom. 8:38: For I am certain that neither death, nor life, et cetera. Because, as it is said in 1 Jn. 3:20, God is greater than our heart. And it is said that, existing in bonds, he converted many. Then, when he says therefore I endure all things, he shows the cause, because it is not the punishment that makes a martyr, but the cause. Now the cause of martyrdom is twofold, namely for the sake of divine honor, and the salvation of one's neighbor. For the sake of God indeed, because Rom. 8:36: for your sake we are put to death all the day long. For the salvation of neighbors, because he says here for the sake of the elect. Jn. 15:13: Greater love has no one, than that someone lay down his life for his friends. 1 Jn. 3:16: because he laid down his life for us, and we ought to lay down our lives for the brethren. And he says for the sake of the elect, because whatever good things happen, they redound especially to the good of the elect, not of the reprobate. And how? That they too may obtain salvation. But is the Passion of Christ sufficient? It must be said that it is, effectively, but the passion of the apostle was expedient in two ways. First, because it gave an example of persisting in the faith; second, because the faith was confirmed, and from this they were led to salvation. And this in Christ, that is, which comes to us through him. Matt. 1:21: for he will save the people from their sins. And this not only salvation, present in grace, but also with heavenly glory. Matt. ch. 5:12: your reward is abundant in the heavens. Then, when he says faithful is the saying, he sets forth the connection of the reward to the merit of martyrdom. And first he sets forth the attestation; second, the consequence, at for if we have died together; third, he confirms it by testimony, at these things put in remembrance. He says therefore faithful is the saying, that is, the word which I shall say is faithful. Apoc., last chapter: these words are most faithful, et cetera. Then, when he says for if, et cetera, he sets forth the consequence. And first concerning the reward of the good; second concerning the punishment of the evil, at if we deny. In the reward of the good there are two things, namely restoration through the resurrection, and the addition of glory to which they will rise. And therefore first he shows that through Christ one comes to the restoration of life; second that through him one comes to the resurrection, at if we endure. He says therefore if we have died together, namely with Christ, and this through the reception of the sacrament in Baptism. Rom. 6:4: for we are buried together with him through Baptism into death. Likewise through penance, by mortifying ourselves. Gal. 6:24: those who are Christ's have crucified their flesh with the vices and lusts. Likewise by dying for the confession of truth, just as Christ also did. Ps. 115:15: Precious in the sight of the Lord is the death of his saints. If therefore we have died together, we shall also live together, that is, just as he rose, so shall we too. Rom. 6:5: If we have been planted together with the likeness of his death, we shall be also of his resurrection. Then he treats of the glory, which the saints merit through the ignominy of death. Lc., last chapter: was it not necessary that Christ should suffer these things? And therefore he says if we endure, namely afflictions and reproaches patiently, we shall reign together, that is, we shall arrive at the kingdom together with him. Matt. 5:10: Blessed are those who persecution, et cetera. Then, when he says if we deny, he shows the consequence as regards punishments. Now one can sin against the faith in two ways: first, by denying it outwardly; second, by laying it aside inwardly. As to the first, he says if we deny, namely before others, he will deny us in judgment. Matt. 25:12: Amen I say to you, I do not know you. To deny is not to acknowledge them to be of his own sheep. As to the second, he says if we do not believe, that is, if we cast faith from the heart, he remains faithful, that is, he holds to his own faithfulness. Hence he remains faithful in his faith, because faith is nothing other than participation in, or adherence to, the truth. But he himself is the very truth, which cannot deny itself. Therefore he is not omnipotent. I respond. From this he is omnipotent, that he cannot deny himself. For to be able to fail pertains rather to impotence, because that something should fail from its own being is through a weakness of its own power. But for Christ to deny himself is to fail from himself; this very fact, therefore, that he cannot deny himself, is the reason of perfect power. Hence sin does not fall upon him, as has been said, nor can he deny his power and his justice without punishing. Matt., last chapter: but he who does not believe will be condemned. But can God not remit the punishment to someone? He can indeed according to the order of his wisdom, but against the order of wisdom and justice, he cannot. Then, when he says these things put in remembrance, et cetera, he confirms it by testimony; as if to say: I admonish along with others, that you may always keep it in your heart, testifying before God, that is, bringing forward as witness him before whom I speak. Then, when he says do not with words, he shows how he resists unbelievers, because first he sets forth in advance the manner of resisting; second he shows what the things are which he resists, at profane. Likewise, first he excludes the undue manner of resisting; second he sets forth the due manner, at diligently. Concerning the first, first he excludes the undue manner; second he assigns the reason, at to nothing. He says therefore do not contend with words. Contention implies a contending in words. It can therefore be understood in two ways, because one speaking with acrimony is depraved in two ways. In one way, if by this one inclines to the favor of falsity, as when someone attacks the truth with a confident clamor. In another way, on account of disorder, as when one uses acrimony either beyond the due measure, or contrary to the quality of the person. But if it is done moderately, and with due circumstances, and on behalf of the truth, it is not a sin. And thus in rhetoric it is one instrument of exhortation. Yet in sacred Scripture it is taken according as it implies disorder. 1 Cor. 11:16: If anyone seems to be contentious among you, we have no such custom, nor does the Church of God. And he says with words, because some dispute only with words of reproach. And this properly is to contend. If this is done not with words only but with true reasons, this is to dispute, not to contend. Then, when he says it is useful for nothing, he shows the reason for the teaching. For moderate disputation, when it is done with reason, is useful for instruction; but when it is with words only, then it is litigious. Therefore he says but to the subverting, and this in two ways: in one way, while what is certain comes into doubt; in another way, because the hearers are scandalized. Prov. 14:23: Where there are many words, there is frequently poverty; hence Jas. 3:16: Where there is envy and contention, there is inconstancy and every wicked work. But should one not dispute about the faith before the people without contention? I respond. A distinction must be made, on the part of the hearers, because either they are being solicited by unbelievers, and then public disputation is useful: because through this the simple are made more instructed when they see those who err refuted. But if they are not being solicited by unbelievers, then disputation is not useful, but dangerous. Likewise a distinction must be made on the part of the one disputing, because if the disputant is prudent, so that he clearly refutes the adversary, then he ought to dispute publicly; but if not, in no way. Then, when he says diligently take heed to yourself, he sets forth the due manner of resisting. And first as regards right intention; second as regards right action; third as regards right doctrine. For he who wishes to dispute must first examine his own intention, whether he is moved by good zeal. Therefore he says to show himself approved to God, who indeed tests the heart. 2 Cor. 10:18: For it is not he who commends himself that is approved, but he whom God commends. Ps. 16:3: You have proved my heart, and visited it by night. Likewise, that he confirm through his works the doctrine which he preaches with his mouth, which unless he does, he is worthy of confusion. Hence he says a workman that need not be ashamed, as if to say: do these things, and thus you will not be put to confusion. Likewise, that he rightly handle the word of truth, teaching things true and useful to the hearers. Hence he adds rightly handling the word of truth, not seeking gain and glory. 2 Cor. 2:17: We are not like many, adulterating the word of God, but out of sincerity, as from God, in the sight of God, we speak in Christ.”

“If we believe not, yet he abideth faithful,.... The Syriac and Ethiopic versions read, "if we believe not him". This may be understood, either of such who are altogether destitute of faith, who do not believe in Christ at all; and particularly do not believe what was just now said concerning his denying such that deny him, but mock and scoff at his coming, and at a future judgment: this unbelief of theirs will not make void his faith or faithfulness; see Rom 3:3, he will abide faithful to his word of threatening; and what he says in Mar 16:16 will be found to be an everlasting truth: or it may be understood of true believers, whose faith sometimes is very low, as to its exercise on Christ, and with reference to their future glory and happiness; but Christ is faithful to all his, covenant engagements for them, to bring them to glory, and to every word of promise concerning their happiness, and to every branch of the faithful saying above mentioned; and he is ever the same in his love to them, and in the efficacy of his blood, righteousness, and sacrifice; and his salvation is an everlasting and unchangeable one; nor do the saints' interest in it, and security by it, depend upon their acts of believing, or their frames, but upon the firmness and unchangeableness of Christ, the object of faith. He cannot deny himself; he cannot go contrary to his word; that would be to act contrary to his nature and perfections, and would be a denying of himself, which is not possible; wherefore his faithfulness will never fail, even though, the faith of his people does, as to the exercise of it.”

“If we believe not; i.e. if we refuse to believe in God, or if after having believed, we depart from our faith, the Almighty still continues faithful; he is still what he was. Our believing in him cannot increase his glory, nor can our disbelief in him cause any diminution thereof, since it is already infinite. (Estius) — The sense may be: when we renounce God, and refuse to believe in him, will he be less powerful to punish us? or, will his menaces be less true or less efficacious? He will effect his work without us, for he will infallibly bring about the salvation of his elect. (Bible de Vence)”

“believe not--"If we are unbelievers (literally, 'unfaithful'), He remains faithful" (Deu 7:9-10). The oldest manuscripts read, "For He cannot (it is an impossibility that He should) deny Himself." He cannot be unfaithful to His word that He will deny those who deny Him, though we be not faithful to our profession of faith in Him (Rom 3:3). Three things are impossible to God, to die, to lie, and to be deceived [AUGUSTINE, The Creed, 1.1], (Heb 6:18). This impossibility is not one of infirmity, but of infinite power and majesty. Also, indirectly, comfort is suggested to believers, that He is faithful to His promises to them; at the same time that apostates are shaken out of their self-deceiving fancy, that because they change, Christ similarly may change. A warning to Timothy to be steadfast in the faith.”