Hell and the Name Caller

and whoever shall say, “You fool,” shall be guilty enough to go into the fiery hell. (5:22c)

Moros (fool) means “stupid” or “dull” and is the term from which we get moron. It was sometimes used in secular Greek literature of an obstinate, godless person. It was also possibly related to the Hebrew marâ which means “to rebel against.” To call someone You fool was to accuse them of being both stupid and godless.

The three illustrations in this verse show increasing degrees of seriousness. To be angry is the basic evil behind murder; to slander a person with a term such as Raca is even more serious, because it gives expression to that anger; and to condemn a person’s character by calling him a fool is more slanderous still. . . .

http://www.macarthurcommentaries.com