22 And we have sent with them our brother, whom we have oftentimes proved diligent in many things, but now much more diligent, upon the great confidence which I have in you.
"And we have sent with them our brother." Behold, again he adds yet another, and him also with an encomium; both his own judgment, and many other witnesses [to him]. "Whom," saith he, "we have many times proved earnest in many things, but now much more earnest." And having praised him from his own good works, he extols him also from his love towards them; and what he said of Titus, that "being very earnest he went forth of his own accord;" this he says of this person also, saying, "but now much more earnest;" laying up beforehand for them the seeds of [the proof of their] love toward the Corinthians.
He adds yet another, calling him a brother and commending him on the basis of trial and judgment, as a man zealous in many things and having proved himself such many times. To elevate speech in this way is characteristic of praise. But now, he says, he has become even more zealous, as if in the hope that you will offer a more generous alms, which he serves.
Then when he says, "And with them we are sending our brother," he deals with the third messenger, namely, Apollos, and he does two things. First, he commends him for his diligence, when he says, whom, namely, Apollos, we have often tested and found earnest in many matters for your salvation, but who is now more earnest than ever. For as is apparent above, Apollos was the first one after the Apostle to preach to the Corinthians: "I planted, Apollos watered, but God gave the growth" (1 Cor. 3:6). But being disturbed at their sin, he departed and put aside the carefulness he had previously for them. But now, hearing of their conversion, he became more diligent than ever for their salvation: "Eager to maintain the unity of the Spirit in the bond of peace" (Eph. 4:3); "The leader, in diligence" (Rom. 12:8).
[AD 407] John Chrysostom on 2 Corinthians 8:22