And the priest shall take an handful of the offering, even the memorial thereof, and burn it upon the altar, and afterward shall cause the woman to drink the water. (Numbers 5:26)
As a reminder to Jehovah to prevent the waters of bitterness from doing harm to the woman if she was innocent. The term is a technical one (Lev. 2:2, 9, 16; 5:12; 6:15; 24:7).