According to Leviticus 4:6–7, Leviticus 4:17, the officiating priest was required to splatter the sacrificial blood in front of the veil of the sanctuary and pour the rest at the base of the altar. During this process some blood might splash onto the priest's clothes.
20 Quiconque en touchera la chair sera sanctifié. S'il en rejaillit du sang sur un vêtement, la place sur laquelle il aura rejailli sera lavée dans un lieu saint.