Deuteronomy 12:6

Thither bring your burnt-offerings Which were wisely appropriated to that one place, for the security of the true religion, and for the prevention of idolatry and superstition, which might otherwise more easily have crept in; and to signify that their sacrifices were not accepted for their own worth, but by God's gracious appointment, and for the sake of God's altar, by which they were sanctified, and for the sake of Christ, whom the altar manifestly represented. Your heave-offerings That is, your first-fruits of corn, and wine, and oil, and other fruits. And these are called the heave-offerings of their hand, because the offerer was first to take these into his hands, and to heave them before the Lord, and then to give them to the priest. Your free-will-offerings Even your voluntary oblations, which were not due by my prescription, but only by your own choice: you may choose what kind of offerings you please to offer, but not the place where you shall offer them.