1 Corinthians 2:15 (KJV 1900)
15 But he that is spiritual judgeth all things, yet he himself is judged of no man.
A spiritual man (as opposed to a natural man) judgeth all things. The word judgeth here doesn’t mean judging someone else in a negative sense. It means to evaluate or examine, like an investigator. It takes a spiritual man to understand.
Proverbs 28:5 (KJV 1900)
5 Evil men understand not judgment:
But they that seek the Lord understand all things.
Yet he himself is judged of no man. The natural man simply will not understand the spiritual man. Again, looking back at verse 14, anything spiritual is foolishness to the natural man.
How can a natural man ever believe? By hearing the word of Christ preached. We pray for their eyes to be open to the Spirit.