Deuteronomy 16:16; Deuteronomy 20:13

16 Three times in a year shall all thy males appear before the LORD thy God in the place which he shall choose; in the feast of unleavened bread, and in the feast of weeks, and in the feast of tabernacles: and they shall not appear before the LORD empty:

13 And when the LORD thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword: