Matthew 5:21-24

21“You have heard that it was said to the men of old, ‘You shall not murder,’ and ‘Whoever murders shall be guilty before the court.’

22But I say to you that everyone who continues to be angry with his brother or harbors malice against him shall be guilty before the court; and whoever speaks [contemptuously and insultingly] to his brother, ‘Raca (You empty-headed idiot)!’ shall be guilty before the supreme court (Sanhedrin); and whoever says, ‘You fool!’ shall be in danger of the fiery hell.

23So if you are presenting your offering at the altar, and while there you remember that your brother has something [such as a grievance or legitimate complaint] against you,

24leave your offering there at the altar and go. First make peace with your brother, and then come and present your offering.