John Chrysostom

"And to wait," he says, "for His Son from heaven, whom He raised from the dead, even Jesus, which delivereth us from the wrath to come." "And to wait," he says, "for His Son from heaven"; Him that was crucified, Him that was buried; to wait for Him from heaven. And how "from heaven"? "Whom He raised from the dead." You see all things at the same time; both the Resurrection, and the Ascension, and the second Coming, the Judgment, the retribution of the just, the punishment of the wicked. …

Homily on 1 Thessalonians 2 ↗

Theophylact of Ohrid

And this is a characteristic of the same method; because in the form of a narrative he taught them to await the Son of God. For the greatest consolation for those who grieve is that the One who suffered has risen and is in heaven, that He will come and deliver us who grieve from the coming wrath, that is, from punishment, as those who have truly pleased Him through faith and a blameless life. But those who cause us grief He will not spare. …

Commentary on 1 Thessalonians ↗

Thomas Aquinas

Since those who serve Him deserve a reward, and because this is the case with the Thessalonians, it remains for them to expect a reward; so Paul says to them, "to wait for his Son," that is, God, descending from heaven. "Be like men who are waiting for their master to come home from the marriage feast" (Lk. 12:36). "Blessed are all those who wait for him" (Is. 30:18). These, however, are the men who girded their loins. …

Commentary on 1 Thessalonians ↗