Albert Barnes Commentary 1 Corinthians 3:21

"Wherefore let no one glory in men. For all things are yours;" — 1 Corinthians 3:21 (ASV)

Therefore, etc. Paul here proceeds to apply the principles he had stated above. Since all were ministers or servants of God; since God was the Source of all good influences; and since whatever might be the pretensions to wisdom among men, it was all foolishness in the sight of God, the inference was clear that no one should glory in man.

They were all alike poor, frail, ignorant, erring, dependent beings. For this reason also, as all wisdom came from God, and as Christians shared alike in the benefits of the instruction of the most eminent apostles, they ought to regard this as belonging to them in common, and not form parties with these names at their head.

Let no man glory in men. (1 Corinthians 1:29). It was common among the Jews to align themselves under different leaders—such as Hillel and Shammai—and for the Greeks also to boast of being the followers of Pythagoras, Zeno, Plato, etc. The same thing began to be evident in the Christian church, and Paul here rebukes and opposes it.

For all things are yours. This is a reason why they should not align themselves into parties or factions under different leaders. Paul specifies what he means by "all things" in the following verses. The sense is that since they had an interest in all that could promote their welfare, as they were common sharers in the benefits of the talents and labors of the apostles, and as they belonged to Christ and all to God, it was improper to be split into factions, as if they derived any peculiar benefit from one set of men or one set of objects. In Paul, in Apollos, in life, death, etc., they had a common interest, and no one should boast that he had any special proprietorship in any of these things.