Matthew 5:22 and Matthew 23:17; Psalm 14:1
On one hand the Jesus says in Matthew 5:22, “But I say unto you, That whosoever is angry with his brother without a cause shall be in danger of the judgment: and whosoever shall say to his brother, Raca, shall be in danger of the council: but whosoever shall say, Thou fool, shall be in danger of hell fire.”
On the other hand Psalm 14:1 “The fool hath said in his heart, There is no God. They are corrupt, they have done abominable works, there is none that doeth good.” And, in Matthew 23:17 Jesus says “Ye fools and blind: for whether is greater, the gold, or the temple that sanctifieth the gold?”
Context. Context. Context. When Jesus said in Matthew 5:22 that we should not call anyone a fool, He was talking about those who did so in unrighteous anger. What do I mean by context? Anger is the main subject of the verse. There is such a thing as a righteous anger which is not sinful (Ephesians 4:26 – “Be ye angry, and sin not:. . .” ) as well as unrighteous anger that is sinful (James 1:20 – “for the anger of man does not achieve the righteousness of God.”).
As for Jesus calling the Pharisees fools, that’s a different story altogether. When God is angry with someone, He always has a righteous reason for His anger. Therefore, He is righteous in His anger. Jesus, being God in flesh (to be discussed another place and time John 1:1,14; 20:28; Colossians 2:9), can righteously be angry, especially the Pharisees, and call them like He sees them. And so you have Matthew 23:17. God does not contradict Himself in calling someone a fool, especially when it is true. He would contradict Himself if He did not call sin what it is.
In the end, Jesus’ condemnation of calling someone a fool is in the context of doing so out of unrighteous anger. Because Jesus was speak to the Pharisees in righteous anger when He called them fools, Matthew 5:22 doesn’t even apply to Matthew 23:17.