Treasury of Scripture Knowledge
"Set apart to me every firstborn male -- the first offspring of every womb among the Israelites, whether human or animal; it is mine."
You must also do this for your oxen and for your sheep; seven days they may remain with their mothers, but give them to me on the eighth day.
But you must not redeem the firstborn of a cow or a sheep or a goat; they are holy. You must splash their blood on the altar and burn their fat for an offering made by fire for a pleasing aroma to the Lord.
You must set apart for the Lord your God every firstborn male born to your herds and flocks. You must not work the firstborn of your bulls or shear the firstborn of your flocks.