Deuteronomy 15:20

then you shall take an awl, and thrust it through his ear to the door, and he shall be your servant forever. Also to your female servant you shall do likewise.

It shall not seem hard to you when you let him go free from you, for he has been double the value of a hired hand as he served you six years. The LORD your God will bless you in all that you do.

You shall dedicate all the firstborn males that are born of your herd and of your flock to the LORD your God. You shall do no work with the firstborn of your herd, nor shear the firstborn of your flock.

If it has any defect—is lame or blind, or has any defect whatever, you shall not sacrifice it to the LORD your God.

You shall eat it within your gates. The unclean and the clean shall eat it alike, as the gazelle and as the deer.

Only you shall not eat its blood. You shall pour it out on the ground like water.