3 And when I come, whomsoever ye shall approve by your letters, them will I send to bring your liberality unto Jerusalem.
[AD 384] Ambrosiaster on 1 Corinthians 16:3
This collection was doubly beneficial, because it helped the saints mentioned above and also the poor people who were in the church.

[AD 407] John Chrysostom on 1 Corinthians 16:3
"And when I arrive, whomsoever you shall approve, them will I send with letters to carry your bounty to Jerusalem."

He said not, "this person," and "that," but, "whomsoever you shall approve," whomsoever you shall choose, thus freeing his ministration from suspicion. Wherefore to them he leaves the right of voting in the choice of those who are to convey it. He is far enough from saying, "The payment is yours, but the privilege of selecting those who are to carry it is not yours." Next, that they might not think him quite absent, he adds his letters, saying, "Whomsoever you approve, I will send with letters." As if he had said, I also will be with them and share in the ministration, by my letters. And he said not, "These will I send to bear your alms," but, "your bounty;" to signify that they were doing great deeds; to mark that they were gainers themselves. And elsewhere he calls it both "a blessing" and "a distribution." [2 Corinthians 9:5-13] The one that he might not make them less active, the other that he might not elate them. But in no case whatever has he called it "alms."

[AD 407] John Chrysostom on 1 Corinthians 16:3
Paul leaves it up to the Corinthians to choose the carriers of his message, so as to avoid showing any partiality.