1 Samuel 2:13-14

13Now the priests would always treat the people in the following way: Whenever anyone was making a sacrifice, while the meat was boiling, the priest’s attendant would come with a three-pronged fork in his hand.

14He would jab it into the basin, kettle, caldron, or pot, and everything that the fork brought up the priest would take for himself. This is what they used to do to all the Israelites when they came there to Shiloh.