Deuteronomy 15:18-20 New English Translation (NET Bible)
18 You should not consider it difficult to let him go free, for he will have served you for six years, twice the time of a hired worker; the Lord your God will bless you in everything you do.
Giving God the Best
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. 20 You and your household must eat them annually before the Lord your God in the place he chooses.