The Apostle Paul
1 Thessalonians 3:9BSB·traditional attribution

How can we adequately thank God for you in return for our great joy over you in His presence?

John Calvin Reformed @genevareformer

9 For what thanksgiving. Not satisfied with a simple affirmation, he intimates how extraordinary is the greatness of his joy, by asking himself what thanks he can render to God; for by speaking thus he declares that he cannot find an expression of gratitude that can come up to the measure of his joy. He says that he rejoices before God, that is, truly and without any pretense.

Matthew Henry Presbyterian @wholebiblehenry

Here we have Paul's great satisfaction upon the return of Timothy with good tidings from the Thessalonians, in which we may observe, I. The good report Timothy made concerning them, Th1 3:6. Without question, he was a willing messenger of these good tidings. Concerning their faith, that is, concerning their stedfastness in the faith, that they were not shaken in mind, nor turned aside form the profession of the gospel.

Commenting on 1 Thessalonians 3:6-10

John Gill Reformed Baptist @doctorgill

For what thanks can we render to God again or you,.... They had given thanks to God for them before, for their faith, love, and patience; see Th1 1:2 and now having received a further account of them, they looked upon themselves bound to give fresh thanks to God for them, for the increase of their faith and love, and for their perseverance, as they...