Numbers 28:3

28:3 You will say to them, ‘This is the offering made by fire which you must offer to the Lord: two unblemished lambs one year old each day for a continual burnt offering.

Numbers 31:19

Purification After Battle

31:19 “Any of you who has killed anyone or touched any of the dead, remain outside the camp for seven days; purify yourselves and your captives on the third day, and on the seventh day.