Deuteronomy 18:4

18:4 You must give them the best of your grain, new wine, and olive oil, as well as the best of your wool when you shear your flocks.

Deuteronomy 15:19

Giving God the Best

15:19 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.