1 Corinthians 2:6

Even though Paul’s preaching of the gospel was simple and clear, there was a depth to his message that he did not want the Corinthians to overlook. Immature Christians cannot understand the real depths of the gospel fully. Later Paul would say the Corinthians were not mature (1 Corinthians 3:1-3).

Paul could have been using the word "mature" as synonymous with "Christian." He may have selected the word "mature" because the Corinthians apparently loved to apply it to themselves.

"All Christians are ’mature’ in the sense that they have come to terms with the message of the cross, while all others, by definition, have not." [Note: Carson, p. 47.]

However, Paul later distinguished the natural person, the spiritual person, and the carnal person (1 Corinthians 2:14 to 1 Corinthians 3:4). Consequently by spiritual he probably meant one who has followed God’s Spirit for some time, not just one who has His Spirit (cf. Hebrews 6:1).

The deep things of God require a type of wisdom that is different from secular wisdom. Presently those who control the climate of public opinion dominate secular wisdom. These rulers are those individuals who set the standard of what people who disregard God’s revelation consider as true (cf. 1 Corinthians 1:20; 1 Corinthians 1:26), particularly those who were responsible for Jesus’ crucifixion (1 Corinthians 2:8). However these people are on the way out because the popular perception of what is true changes and because Christ will end their rule eventually (1 Corinthians 15:24-25; Colossians 2:15).