Rom 2:16

“If God will judge the secrets of men … surely the God who will judge is he to whom belong both the law and that nature which is the rule for those who do not know the law. But how will he conduct this judgment? "According to my gospel," says the apostle, "by Christ Jesus." The law and nature are vindicated by the gospel and Christ.”

“Now he did not observe how much this clause of the sentence made against him: "For God, who commanded the light to shine out of darkness, hath shined in our hearts, to (give) the light of the knowledge (of His glory) in the face of (Jesus) Christ." Now who was it that said; "Let there be light? " And who was it that said to Christ concerning giving light to the world: "I have set Thee as a light to the Gentiles" -to them, that is, "who sit in darkness and in the shadow of death? " (None else, surely, than He), to whom the Spirit in the Psalm answers, in His foresight of the future, saying, "The light of Thy countenance, O Lord, hath been displayed upon us.”

“Who can doubt that a trial is properly conducted when there are accusers and defenders and witnesses all present?… See therefore how on that day, when God will judge the secrets of men, our thoughts will either accuse or defend our soul—not the thoughts which we will have then but the ones which we have now.”

“The awe-inspiring countenance of the Judge will compel you to speak the truth. Even if you are silent, it will convict you. You will rise clothed either in your sins or in your just deeds. The Judge himself declared this.”

“Men sit as judges of the external things only. It is God who judges things hidden. For Scripture says: "Man looks on the outward appearance, but God looks upon the heart." When Christ judges, then God is the judge.”

“"In the day when God shall judge the secrets of men by Jesus Christ, according to my Gospel." See how he again puts that day before them, and brings it close to them, battering down their conceit, and showing, that those were to be the rather honored who without the Law strove earnestly to fulfil the things of the Law. ... For the conscience and reason doth suffice in the Law's stead. By this he showed, first, that God made man independent, so as to be able to choose virtue and to avoid vice. ... And why does he put the words "accusing or else excusing?"-for, if they have a Law written, and show the work of it in them, how comes reason to be able to accuse them still? But he is not any longer speaking of those only who do well, but also of mankind (Gr. the nature) universally. For then our reasonings stand up, some accusing and some excusing. And at that tribunal a man needeth no other accuser. Then to add to their fear, he does not say the sins of men, but the secrets of men. For since he said, "Thinkest thou, that judgest them that do such things, and doest the same, that thou shalt escape the judgment of God;" that thou mayest not expect such a sentence as thou passest thyself, but mayest know, that that of God is far more exact than thine own, he brings in, "the secrets of men," and adds, "through Jesus Christ according to my Gospel." For men sit in judgment upon overt acts alone. And above too he spake of the Father alone, but as soon as he had crushed them with fear, he brought in the mention of Christ also. But he does not do barely this, but even here, after having made mention of the Father, he so introduceth Him. And by the same things he raises the dignity of his preaching. For this preaching, he means, openly speaks out what nature taught by anticipation. Do you see with what wisdom he has bound them both to the Gospel and to Christ, and demonstrated that our affairs come not here to a stand, but travel further. And this he made good before also, when he said, "thou treasurest up to thyself wrath against the day of wrath:" and here again, "God shall judge the secrets of men."”

“Paul says that there is a mental debate when we decide after long deliberation what we should and should not do. On the day of the Lord we shall be judged by this. This proves that we were not ignorant of good and evil. Or perhaps it means that on the day of judgment our conscience and our thoughts will appear before our eyes like history lessons to be learned; they will either accuse us or excuse us.”

“Paul continually preached that there will be a day of judgment and that it will be necessary to have believed in Christ in order to escape punishment.”

“And to increase the fear, he did not say: sins, but: "secret deeds." People can judge only manifest deeds, but God, he says, will judge the secret deeds through Jesus Christ, that is, the Father through the Son, because the Father judges no one, but has given all judgment to the Son (John 5:22). You can also understand the words "through Jesus Christ" this way: according to my gospel, entrusted to me by Jesus Christ. Here he suggests that the gospel preaches nothing contrary to nature, but proclaims the very same thing that was originally implanted in people by nature itself, that is, that the gospel also testifies of judgment and punishment.”

“But because testimony, accusation, and defense occur during a trial, he mentions the time, when he says in the day. He says this not to designate the quality of the time but the disclosure of things hidden: I will bring to light the things now hidden in darkness (1 Cor 4:5). Yet it is sometimes called night on account of the uncertainty of that hour: at midnight there was a cry (Matt 25:6). The accusing or defending thoughts are not those which will arise on the day of judgment, because on that day each one's salvation or damnation will be clear to him; rather, such thoughts as exist now and the testimony of conscience that exists now will be represented to a man on that day by divine power, as Augustine says in The City of God II. Indeed, the recognition of those thoughts that remain in the soul seems to be nothing less, as a Gloss says, than the debt of punishment or the reward, which follows them. Then he shows the author of the judgment, when he says, when God shall judge: he will judge the world with justice (Ps 96:13). He also describes what the judgment will concern, when he says, the secrets of men, matters about which men cannot now judge. He will bring to light the things now hidden in darkness (1 Cor 4:5). He also shows the teaching from which faith in this judgment is had when he says, according to my Gospel, i.e., preaching by me: on the day of judgment men will render account for every careless word (Matt 12:36). He says according to my Gospel, although he could not say, my baptism, and be a minister of both, because in baptism a man's diligence effects nothing, but in preaching the Gospel the preacher's industry achieves something: when you read this you can perceive my insight in the mystery of Christ (Eph 3:4). Then he mentions the judge, when he says, by Christ Jesus, who has been appointed by God to be judge of the living and the dead (Acts 10:42); the Father has given all judgment to the Son (John 5:20), who will appear to the good and the wicked during the judgment: to the good in the glory of the Godhead: your eyes will see the king in his beauty (Isa 33:17), but to the wicked in his human form: every eye will see him (Rev 1:7).”

“There are two thoughughts inside a man which will accuse each other—the good and the evil. The good accuses the evil because it has denied the truth. The evil accuses the good because it has not done what it knows to be right. One who knows that the church is good and true but persists in heresy or schism will be judged guilty. Other thoughts will excuse, insofar as one has done what is expedient to do. He will say inwardly: "In my mind I have always thought it expedient to do what I have done. This was my faith." He will have a better case, even though he will still have to be corrected, because his conscience will not accuse him on the day of judgment. This is how the secret things of men will be judged by Jesus Christ our Lord on the day of judgment.”