1 Corinthians 2:14–15 (NASB)
 But a° natural man does not accept the things of the Spirit of God, for they are foolishness to him; and he cannot understand them, because they are spiritually appraised°.  But he who is spiritual appraises all things, yet he himself is appraised by no one.
1 Corinthians 2:14a Or an unspiritual
1 Corinthians 2:14b Or examined
The word translated “appraise” here literally means “discerned or examined”. What the first verse of this passage is saying is that spiritual things can only be understood by those with the Holy Spirit. I think this is what Jesus meant when He said, “don’t throw your pearls before swine.”
The second verse of this passage is an echo of what Jesus told his disciples in the upper room and what Jesus told Nicodemus early in His ministry. The Holy Spirit will teach us all things and help us discern the spiritual aspects of all things. Yet, while we have been given understanding and discernment, we will not be understandable when we walk in the Spirit.
All this is not to say that we aren’t supposed to be witnessing to people, but …
1 Corinthians 1:21 (NLT)
Since God in his wisdom saw to it that the world would never find him through human wisdom, he has used our foolish preaching to save all who believe.
Matthew 7:6; 1 Corinthians 1:18; John 14:26; John 3:8; Romans 10:14