Why does Paul say he fed the Corinthians with milk instead of meat?
Paul fed the Corinthians milk because they were still spiritual babes, carnal believers controlled by the Old Adam rather than the Holy Spirit. Though saved, in Christ, and in the Body of Christ, they were too weak and fleshly minded for solid meat, so he gave them basic teaching suited to their immature state.
Les explains that "carnal" here refers to believers who have not really come out of the fleshly experience and are still under the control of the Old Adam rather than the Holy Spirit. In Romans 8, Paul uses "carnal" for the unsaved individual, but here he speaks of saved believers who are in Christ yet still so weak spiritually that he calls them babes. Paul says, "I have fed you with milk." This is an analogy with the human: you do not give a newborn baby solid food but start with milk, and it is the same way with a believer. Les says the Lord gave him patience with new believers; he does not expect them to suddenly comprehend all the deep things of God's Word, but he looks for growth. God expects growth from His children. The Corinthians were still so steeped in the flesh that Paul got uptight in his first and second letters, yet he calls them believers. They had been born again and placed into the Body of Christ, but they were still so fleshly minded. Therefore Paul fed them milk rather than meat because they were not ready for the deeper things.
I have fed you with milk, and not with meat: for hitherto ye were not able to bear it, neither yet now are ye able.