1 Corinthians 3:1
1. And I—that is, as the natural (animal) man cannot receive, so I also could not speak unto you the deep things of God, as I would to the spiritual; but I was compelled to speak to you as I would to MEN OF FLESH. The oldest manuscripts read this for "carnal." The former (literally, "fleshy") implies men wholly of flesh, or natural. Carnal, or fleshly, implies not they were wholly natural or unregenerate (1Co 2:14), but that they had much of a carnal tendency; for example their divisions. Paul had to speak to them as he would to men wholly natural, inasmuch as they are still carnal (1Co 3:3) in many respects, notwithstanding their conversion (1Co 1:4-9).
babes—contrasted with the perfect (fully matured) in Christ (Col 1:28; compare Heb 5:13, 14). This implies they were not men wholly of flesh, though carnal in tendencies. They had life in Christ, but it was weak. He blames them for being still in a degree (not altogether, compare 1Co 1:5, 7; therefore he says as) babes in Christ, when by this time they ought to have "come unto a perfect man, unto the measure of the stature of the fulness of Christ" (Eph 4:13). In Ro 7:14, also the oldest manuscripts read, "I am a man of flesh." 1 Corinthians 14:20
20. Brethren—an appellation calculated to conciliate their favorable reception of his exhortation.
children in understanding—as preference of gifts abused to nonedification would make you (compare 1Co 3:1; Mt 10:16; Ro 16:19; Eph 4:14). The Greek for "understanding" expresses the will of one's spirit, Ro 8:6 (it is not found elsewhere); as the "heart" is the will of the "soul." The same Greek is used for "minded" in Ro 8:6. men—full-grown. Be childlike, not childish.