1 Samuel 10:8

And thou shalt go down before me to Gilgal, in case he should be inclined to go there for the sake of bringing a sacrifice; and, behold, I will come down unto thee, to offer burnt offerings, and to sacrifice sacrifices of peace-offerings, for Saul could not do this work, since it pertained to the priestly office; seven days shalt thou tarry, till I come to thee and show thee what thou shalt do. The reference is not to a general practice, but to a specific instance, 1 Samuel 13:8, for the Lord still transmitted certain commands through the mouth of Samuel.