מדרש על ויקרא 4:34

3) (Vayikra 4:33): "And he shall place his hand on the head of the sin-offering" — to include for semichah: the sin-offering of the Nazirite, of the leper, and of the defiler of the sanctuary. "And he shall slaughter it as a sin-offering" — expressly as a sin-offering. (Vayikra 4:34): "And the Cohein shall take from the blood of the sin-offering" — expressly for a sin-offering. (Vayikra 4:35): "And the Cohein shall atone for him for his sin" — expressly for his sin. — whence they said: If (in sacrificing a sin-offering), he did not slaughter it, or receive (the blood), or bring it (on the altar), or sprinkle it — to that end — it is pasul.