1 Corinthians 2:4

that the natural man cannot understand it.
Overview - 1 Corinthians 2
He declares that his preaching, though it bring not excellency of speech, or of human wisdom, yet consists in the power of God;
and so far excels the wisdom of this world, and human sense,
Treasury of Scripture Knowledge

1 Corinthians 2:4  (King James Version)
And my speech and my preaching was not with enticing words of man's wisdom, but in demonstration of the Spirit and of power:
 


my speech
Acts 20:27

not
1 Corinthians 2:1 1 Corinthians 2:13 ; 1:17 Judges 14:15 ; 16:5 2 Samuel 14:17-20 ; 15:2-6 1 Kings 22:13 1 Kings 22:14
2 Chronicles 18:19-21 ; Proverbs 7:21 ; 20:19 Jeremiah 20:10 ; Ezekiel 13:6 Ezekiel 13:10 Ezekiel 13:11 ; Romans 16:18
Colossians 2:4 ; 2 Peter 1:16 ; 2:18

enticing
or, persuasible.
Acts 26:28 ; Galatians 1:10

but
4:20 John 16:8-15 ; Romans 15:19 ; 1 Thessalonians 1:5 ; 1 Peter 1:12