Leviticus 17:5

‘Now if his offering is a sacrifice of peace offerings, if he is going to bring near one from the herd, whether male or female, he shall bring it near without blemish before Yahweh.

‘And from the sacrifice of peace offerings he shall bring near as an offering by fire to Yahweh its fat, the entire fat tail which he shall remove close to the backbone, and the fat that covers the entrails and all the fat that is on the entrails,

The people were still sacrificing on the high places because there was no house built for the name of Yahweh until those days.

‘So they will complete the days. And it shall be that on the eighth day and onward, the priests shall offer on the altar your burnt offerings and your peace offerings; and I will accept you,’ declares Lord Yahweh.”

“But the Levitical priests, the sons of Zadok, who kept the responsibility of My sanctuary when the sons of Israel went astray from Me, shall come near to Me to minister to Me; and they shall stand before Me to bring near to Me the fat and the blood,” declares Lord Yahweh.