Purification, in its legal and technical sense, is applied to the ritual observances whereby an Israelite was formally absolved from the taint of uncleanness. The essence of purification, in all cases, consisted in the use of water, whether by way of ablution or aspersion; but in the majora delicta of legal uncleanness, sacrifices of various kinds were added, and the ceremonies throughout bore an expiatory character. Ablution of the person and of the clothes was required in the cases mentioned in Lev. 15:18; 11:25, 40; 15:16, 17. In cases of childbirth the sacrifice was increased to a lamb of the first year, with a pigeon or turtle-dove. Lev. 12:6. The ceremonies of purification required in cases of contact with a corpse or a grave are detailed in Num. 19. The purification of the leper was a yet more formal proceeding, and indicated the highest pitch of uncleanness. The rites are described in Lev. 14:4-32. The necessity of purification was extended in the post-Babylonian period to a variety of unauthorized cases. Cups and pots and brazen vessels were washed as a matter of ritual observance. Mark 7:4. The washing of the hands before meals was conducted in a formal manner. Mark 7:3. What may have been the specific causes of uncleanness in those who came up to purify themselves before the Passover, John 11:55, or in those who had taken upon themselves the Nazarites’ vow, Acts 21:24, 26, we are not informed. In conclusion it may be observed that the distinctive feature in the Mosaic rites of purification is their expiatory character. The idea of uncleanness was not peculiar to the Jew; but with all other nations simple ablution sufficed: no sacrifices were demanded. The Jew alone was taught by the use of expiatory offerings to discern to its fullest extent the connection between the outward sign and the inward fount of impurity.