The Apostle Paul
Romans 1:12ESV·traditional attribution

that is, that we may be mutually encouraged by each other’s faith, both yours and mine.

John Calvin Reformed @genevareformer

12. Being not satisfied with this modest statement, he qualifies it, and shows, that he did not so occupy the place of a teacher, but that he wished to learn also from them; as though he said, “I desire so to confirm you according to the measure of grace conferred on me, that your example may also add courage (alacritatem — alacrity) to my faith...

Matthew Henry Presbyterian @wholebiblehenry

We may here observe, I. His thanksgivings for them (Rom 1:8): First, I thank my God. It is good to begin every thing with blessing God, to make that the alpha and omega of every song, in every thing to give thanks. - My God. He speaks this with delight and triumph.

Commenting on Romans 1:8-15

John Gill Reformed Baptist @doctorgill

That is, that I may be comforted together with you,.... This is a further explanation of his view, in being desirous of coming to them, and preaching: the Gospel among them; for what makes for establishment, makes for comfort; and what makes for comfort, makes for establishment; and when souls are established, ministers are comforted as well as they; and whilst ministers are imparting their...