Zevachim 51b זבחים נ״א ב

This teaches that you must give a base to the altar of the burnt offering, i.e., that the remainder of any blood placed on the altar must be poured on the base.

The Gemara explains: Because if it enters your mind that the verse states this simply to teach as it is written, concerning this offering alone, why do I need these verses with regard to the sin offering of a king? If you would answer: The verses are needed to teach the halakha that the remainder of the blood must be poured on the external altar rather than on the inner altar, then the question remains: Is there any need for the Torah to teach this about the remainder? But the sprinklings of blood themselves are performed on the external altar, so why would one think that the remainder of the blood should be poured on the inner altar?

And if you would say that one might mistakenly say that the priest reverses the sprinklings,