Jamieson, Fausset and Brown on Ephesians 1:15

15. Wherefore--because ye are in Christ and sealed by His Spirit (Ep 1:13, 14).

I also--on my part, in return for God's so great benefits to you.

after I heard--ever since I have heard. Not implying that he had only heard of their conversion: an erroneous argument used by some against the address of this Epistle to the Ephesians (see on Ep 1:1); but referring to the report he had heard since he was with them, as to their Christian graces. So in the case of Philemon, his "beloved fellow laborer" (Phm 1), he uses the same words (Phm 4, 5).

your faith--rather, as Greek, "the faith among you," that is, which many (not all) of you have.

love unto all the saints--of whatever name, simply because they are saints. A distinguishing characteristic of true Christianity (Ep 6:24). "Faith and love he often joins together. A wondrous pair" [Chrysostom]. Hope is added, Ep 1:18.