1Thess 3:13

“And again: "For what is our hope, or joy, or crown of rejoicing? Are not even ye in the presence of our Lord God, Jesus Christ, at His coming? " Likewise: "Before God, even our Father, at the coming of the Lord Jesus Christ, with the whole company of His saints." He teaches them that they must "not sorrow concerning them that are asleep," and at the same time explains to them the times of the resurrection, saying, "For if we believe that Jesus died and rose again, even so them also which sleep in Jesus shall God bring with Him.”

“"To the end He may establish your hearts unblamable in holiness before our God and Father, at the coming of our Lord Jesus Christ with all His saints." He shows that love produces advantage to themselves, not to those who are loved. I wish, he says, that this love may abound, that there may be no blemish. He does not say to stablish you, but your hearts. "For out of the heart come forth evil thoughts." (Matt. xv. 19) For it is possible, without doing anything, to be a bad man; as for example, to have envy, unbelief, deceit, to rejoice at evils, not to be loving, to hold perverted doctrines, all these things are of the heart; and to be pure of these things is holiness. For indeed chastity is properly by preeminence called holiness, since fornication and adultery is also uncleanness. But universally all sin is uncleanness, and every virtue is purity. For, "Blessed," it is said, "are the pure in heart." (Matt. v. 8) By "the pure" He means those who are in every way pure. For other things also know how to pollute the soul, and no less. For that wickedness defiles the soul, hear the prophet, saying, "O Jerusalem, wash thine heart from wickedness." (Jer. iv. 14) And again, "Wash you, make you clean, put away the wickednesses from your souls." (Isa. i. 16, Sept) He did not say "fornications," so that not only fornication, but other things also defile the soul. "To establish your hearts," he says, "unblamable in holiness before our God and Father, at the coming of our Lord Jesus Christ with all His saints." Therefore Christ will then be a Judge, but not before Him (only), but also before the Father we shall stand to be judged. Or does he mean this, to be unblamable before God, as he always says, "in the sight of God," for this is sincere virtue-not in the sight of men? It is love then that makes them unblamable. For it does make men really unblamable.”

“The Apostle shows that love benefits those who love, not those who are loved. "May the Lord fill you," he says, "with love, so as to establish your hearts." By "the Lord" understand the Spirit, as Basil the Great also interpreted this. For who else will establish them blameless before God and Father at the coming of Christ, if not the Spirit entirely? He did not say: will establish you, but: "your hearts. For out of the heart proceed evil thoughts" (Mt. 15:19). It is possible to be evil without doing any evil deed, such as being envious, deceitful, bearing grudges, or holding to perverted teaching. Therefore, a person is truly blameless when he purifies his heart; then he also has holiness. For although holiness chiefly refers to chastity, just as impurity refers to fornication and adultery, in general every sin is impurity and every virtue is holiness. The Apostle wishes them to be blameless before God and Father, both now (for this is true virtue — before God, not before men, since human judgment is unstable) and at the coming of Christ, for He too will judge us before the face of His Father. Therefore, may you be, he says, blameless, as are all the saints.”

“But for what purpose does Paul pray? So that he may establish your hearts unblamable in holiness, that is, that nobody can complain about you; "...righteous before God, walking in all the commandments and ordinances of the Lord blameless" (Lk. 1:6). In holiness before our God who sees the heart: "In holiness and righteousness before him all the days of our life" (Lk. 1:75). And this shall be manifest at the coming of our Lord Jesus, that He may find you holy, who shall come with all his saints; that you might be in His presence, just as all the saints are before Him.”