Skeptics argue that Jesus contradicted Himself by warning that whoever says "Thou fool" will be in danger of hellfire (Matthew 5:22), yet later calling the Pharisees "fools" (Matthew 23:17, Luke 11:40) and appearing to contradict the Psalmist (Psalm 14:1).

Reading Matthew 5:22 in its entirety resolves the issue: "That whosoever is angry with his brother without a cause shall be in danger of the judgment... but whosoever shall say, Thou fool, shall be in danger of hell fire." Jesus is explicitly talking about relations with one's brother (fellow believers) and words said in anger to that brother. In Matthew 23:17, Jesus is not talking to His brethren, but to the Pharisees. In line with Psalm 14:1, He was referring to the Pharisees as unbelievers in His work. Thus, the warning in Matthew 5 does not apply here.

Furthermore, in Luke 11:40, the Greek word used for "foolish" is aphron, not the word moros used in Matthew 5:22. aphron carries a connotation of being an "unbeliever" rather than the reference to plain stupidity that moros carries.

Finally, while skeptics may object that this language is offensive, the polemic registered here was well within the range of stock accusations made among various parties in first-century Judaism. Such exchanges of rhetoric were perfectly acceptable in that time period, and skeptics cannot arbitrarily impose modern sensibilities upon ancient cultures.