Matthew 5:21

21 `Ye heard that it was said to the ancients: Thou shalt not kill, and whoever may kill shall be in danger of the judgment;

Matthew 5:21 In-Context

19 `Whoever therefore may loose one of these commands -- the least -- and may teach men so, least he shall be called in the reign of the heavens, but whoever may do and may teach [them], he shall be called great in the reign of the heavens.
20 `For I say to you, that if your righteousness may not abound above that of the scribes and Pharisees, ye may not enter to the reign of the heavens.
21 `Ye heard that it was said to the ancients: Thou shalt not kill, and whoever may kill shall be in danger of the judgment;
22 but I -- I say to you, that every one who is angry at his brother without cause, shall be in danger of the judgment, and whoever may say to his brother, Empty fellow! shall be in danger of the sanhedrim, and whoever may say, Rebel! shall be in danger of the gehenna of the fire.
23 `If, therefore, thou mayest bring thy gift to the altar, and there mayest remember that thy brother hath anything against thee,
Young's Literal Translation is in the public domain.