Leviticus 3:16
And the priest shall burn them upon the altar: it is the food of the offering made by fire for a sweet savour: all the fat is the LORD’s. And the priest shall burn them upon the altar: it is the food of the offering made by fire for a sweet savour: all the fat is the LORD’s.
The direction was given by Christ Himself to Israel as part of the instructions for sacrificial offerings. It was no meaningless outward form, but was designed to represent His own ministry and death as the Saviour who would bear the sins of the world and die for its redemption. Its particular place is in the peace-offering service, in which part of the sacrifice was reserved for the people. After prayer for God's acceptance and blessing, the people shared that reserved portion together in a sacred feast. That service was meant to foster true devotion, piety, kindness and sympathy, not mere ceremony or self-gratification.