And thither ye shall bring your burnt offerings, and your sacrifices, and your tithes, and heave offerings of your hand, and your vows, and your freewill offerings, and the firstlings of your herds and of your flocks: (Deuteronomy 12:6)
This is a reference to the “firstfruits,” of corn, wine, oil, and other products of the earth brought in person (Num. 18:11, 12; Deut. 18:4; 26:4, 10). The worshiper had raised it by his own labor and gathered it by his own hand.