Zevachim 101 - An Argument Between Moses and Aaron
On the day when two of Aaron's sons died, Aaron with his remaining two sons did not eat the sacrifice of the New Moon but burned it instead. Moses began investigating why this happened .
He said " Why did you not eat the sin-offering of New Moon?? " Moses asked Aaron, "Perhaps its blood was accidentally brought into the Most Holy chamber?" But Aaron replied, "Behold, it was not brought inside."
Moses then asked, "Perhaps it went outside the boundary," but Aaron replied that it was always within. Moses then suggested, "Perhaps you offered it when you were mourners and thereby disqualified it?" - to which Aaron replied that he, the High Priest, has brought it, and the High Priest does not disqualify an offering even as a mourner.
Having exhausted all possibilities, Moses demanded why it was not eaten, when they were commanded to do so , and Aaron replied, "Today such things (as the death of my sons) happened, so perhaps you did not hear right what God has said, but eating should apply only to the inauguration sacrifices, and not the New Moon ones ."
Moses agreed completely and said, " I heard it but forgot ."
Art: Johann Hamza - A Good Dinner