Leviticus 15:14

15:14 Then on the eighth day he is to take for himself two turtledoves or two young pigeons, and he is to present himself before the Lord at the entrance of the Meeting Tent and give them to the priest,

Leviticus 22:27

22:27 “When an ox, lamb, or goat is born, it must be under the care of its mother seven days, but from the eighth day onward it will be acceptable as an offering gift to the Lord.

Leviticus 25:22

25:22 and you may sow the eighth year and eat from that sixth year’s produce – old produce. Until you bring in the ninth year’s produce, you may eat old produce.