Leviticus 27:26
"'But the firstborn of the beasts that pertain unto the LORD, may no man sanctify: whether it be ox or sheep, for they are the LORD's already.
Exodus 13:2
"Sanctify unto me all the firstborn that open all manner matrices among the children of Israel, as well of men as of beasts: for they are mine."
Exodus 13:12-13
then thou shalt appoint unto the LORD all that openeth the matrix, and all the firstborn among the beasts which thou hast if they be males.
Exodus 22:30
likewise shalt thou do of thine oxen and of thy sheep. Seven days it shall be with the dam, and the eighth day thou shalt give it me.
Numbers 18:17
"But the firstborn of oxen, sheep and goats shall not be redeemed. For they are holy, and thou shalt sprinkle their blood upon the altar, and shalt burn their fat to be a sacrifice of a sweet savour unto the LORD.
Deuteronomy 15:19
All the firstborn that come of thine oxen and of thy sheep that are males, thou shalt hallow unto the LORD thy God. Thou shalt do no service with the firstborn of thy sheep: