1 Corinthians 3:1 (NKJV)
3 And I, brethren, could not speak to you as to spiritual people but as to carnal, as to babes in Christ.
The KJV does not add the word people. It is not in the Greek. Literally, Paul writes, …could not speak to you as spiritual. In this case he refers to those brethren who were filled with and governed by the Spirit of God; but these in the Corinthian church were not. He had to take a different approach when he addressed them.
But as unto carnal. The word is, σαρκικός [sarkikos /sar·kee·kos/] and it is from the root word, sarx which means the flesh or the body. Sarkikos then is someone under the control of their bodily or fleshly appetites.
As to babes in Christ. Babies have no control over their desires. When they are hungry, they cry, if they have to wait too long they turn red in the face and scream. They are under control of their flesh! Babies cannot be reasoned with. They can’t chew, and in fact don’t even know what meat is. All a mother can do is feed them milk.
Paul could only address these church members as babies in Christ. In other words, while they may have had worldly wisdom, they were spiritually immature.
Can a Christian then be carnal? The answer is clear….Yes.