From Commentary on 2 Thessalonians (ca. 1270)
Paul says we are bound to give thanks always to God for you, brethren. For since he commended them in the first epistle for their faith and charity and for the other goods in which they abounded, he says “we are bound to give thanks always to God for you, because I consider the good you have as mine”. “I have no greater joy than to hear that my children walk in truth” (3 John 1:4). And he gives thanks to God, without whom nothing good can come to pass. And this is as it is fitting, because we give thanks for great goods. “Since God has wondrously liberated us from great dangers, let us give thanks” (2 Macc. 1:11).
Why? Because spiritual goods grow exceedingly. For such goods are not safely guarded unless a man progresses in them. Now among these gifts of God the first is faith, through which God dwells in us, and our progress in faith is in connection with the understanding, “to have Christ through faith in your hearts” (Eph. 3:17). And so a man progresses through knowledge, devotion, and adherence. The second is charity, through which God is present in us by his effect; “God is charity, and he who abides in charity abides in God, and God in him” (1 John 4:16). And for this reason, he says, and the charity of every one of you towards each other abounds; “in abundant justice there is the greatest strength” (Prov. 15:5). But concerning charity towards the brotherhood I have no need to write to you, “for you yourselves have learned from God to love one another” (1 Thess. 4:9).
St. Thomas Aquinas (ca. 1225-1274) is sometimes described as the greatest thinker of the medieval Church. His various theological treatises, above all his Summa Theologica, seek to reconcile inherited Christian teaching with the newly rediscovered metaphysical writings of Aristotle. His Commentary on 2 Thessalonians is a text reconstructed from lectures he gave at the University of Paris. His modern feast day is January 28. This text has been slightly adapted for contemporary readers.