THE FIRST EPISTLE OF ST. PAUL, THE APOSTLE, TO THE THESSALONIANS.
PREFACE of HAYDOCK COMMENTARY
St. Paul having preached with success at Thessalonica, the chief city of Macedonia, wrote to them this letter, to confirm them in the Christian faith and in the practice of virtue. This, in order, is the first epistle of St. Paul. He wrote it about the year fifty-two[A.D. 52], as it is thought, from Corinth. (Witham) — St. Paul having preached the gospel in this place, converted some Jews and a great number of Gentiles; but the unbelieving Jews, envying his success, raised such a commotion against him, that he and his companion Silvanus were obliged to quit the city. Afterwards he went to Athens, where he had heard that the converts in Thessalonica were under a severe persecution ever since his departure; and lest they should lose their fortitude, he sent Timothy to strengthen and comfort them in their sufferings. In the mean time St. Paul came to Corinth, where he wrote this first epistle and also the second to the Thessalonians, both in the same year, being the nineteenth after our Lord’s ascension. (Challoner) — St. Paul preached the faith in this city, assisted by Silas or Silvanus, whose name is joined with the apostle’s in this letter. See Acts xvii. Being driven away from this city by the violence of the Jews, he left Timothy and Silas in Macedonia, to confirm the new converts in their faith. But having afterwards called them to him, and hearing of their constancy and perseverance, he writes this epistle to encourage them and praise them. It is the first in time of all St. Paul’s epistles, and filled with the most affectionate expressions of love and tenderness for his spiritual children in Jesus Christ. In the latter part of the epistle, he gives some short instructions concerning the state of souls after death, and the coming of the last day; as his companions had informed him that strange reports concerning these two articles were in circulation at Thessalonica, to the disturbance of the faithful. (Calmet, Estius, and others.) — The first three chapters are to confirm and comfort the Thessalonians against the temptations of persecution; the other two are to exhort them to live up to the precepts he delivers them.
Commentary of St Thomas Aquinas

PROLOGUE
The waters increased, and bore up the ark and it rose above the earth (Gen. 7:17).
These words are appropriate to the contents of this letter. The Church is symbolized by the ark, as is stated in 1 Peter 3, for as in the ark a few souls were saved, the others perishing, so also in the Church a few, that is, only the elect, will be saved.
The “waters” signify tribulations. First, because flooding waters strike like tribulations: “And the rain fell, and the floods came, and the winds blew and beat upon that house” (Matt. 7:25). Yet the Church is not shaken by the force of the floods; so Matthew adds, “but it did not fall.
Secondly, because water extinguishes fire: “Water extinguishes a blazing fire” (Sir. 3:30). Similarly, tribulations diminish the force of desires so that men do not follow them at will; but they do not diminish the true charity of the Church: “Many waters cannot quench love, neither can floods drown it” (Cant. 8:7).
Thirdly, because waters inundate by flooding: “Water closed over my head” (Lam. 3:54). Yet the Church is not overcome by them: “The waters closed in over me, the deep was round about me; weeds were wrapped about my head” (Jon. 2.6). And just before this, “Yet would I again look upon your holy temple.”
Therefore, the Church is not destroyed but uplifted: first, by lifting the mind to God, as is clear from Gregory: “The evil things which bear down upon us here compel us to go to God.” “And in their distress they seek me” (Ho. 6: 1). Secondly, the Church is raised up through spiritual consolation: “When the cares of my heart are many, thy consolations cheer my soul (Ps. 94-19); “For as we share abundantly in Christ’s sufferings, so through Christ we share abundantly in comfort too” (2 Cor. 1:5). Thirdly, the Church is upraised by increasing the number of the faithful; for God has spread the Church in time of persecution: “But the more they were oppressed, the more they multiplied and the more they spread abroad” (Ex. 1: 12).
It seems then that these words are appropriate to this letter because the Thessalonians stood firm after suffering many tribulations. Let us, therefore, look at the text.
