1550s, from Latin asperges, 2nd person singular future indicative of aspergere "to scatter, strew upon, sprinkle," from ad "to" (see ad-) + spargere "to sprinkle" (see sparse). The word is taken from the phrase Asperges me, Domine, hyssopo et mundabor, from Psalm 51 (Vulgate), sung during the rite of sprinkling a congregation with holy water.