Clean, Unclean
The Old Testament. How Uncleanness Was Contracted and Treated. In Old Testament times the ordinary state of most things was "cleanness, " but a person or thing could contract ritual "uncleanness" (or "impurity") in a variety of ways: by skin diseases, discharges of bodily fluids, touching something dead ( Num 5:2 ), or eating unclean foods ( Lev 11 ; Deut 14 ).
An unclean person in general had to avoid that which was holy and take steps to return to a state of cleanness. Uncleanness placed a person in a "dangerous" condition under threat of divine retribution, even death ( Lev 15:31 ), if the person approached the sanctuary. Uncleanness could lead to expulsion of the land's inhabitants ( Lev 18:25 ) and its peril lingered upon those who did not undergo purification ( Lev 17:16 ; Num 19:12-13 ).
Priests were to avoid becoming ritually defiled ( Leviticus 21:1-4 Leviticus 21:11-12 ), and if defiled, had to abstain from sacred duties. An unclean layperson could neither eat nor tithe consecrated food ( Lev 7:20-21 ; Deut 26:14 ), had to celebrate the Passover with a month's delay ( Num 9:6-13 ), and had to stay far away from God's tabernacle ( Num 5:3 ).
Purification varied with the severity of the uncleanness. The most serious to least serious cases in descending order were: skin disease (Lev. 13-14), childbirth (Lev. 12), genital discharges ( Leviticus 15:3-15 Leviticus 15:28-30 ), the corpse-contaminated priest ( Eze 44:26-27 ), the corpse-contaminated Nazirite ( Nu 6:9-12 ), one whose impurity is prolonged ( Lev 5:1-13 ), the corpse-contaminated layperson ( Num 5:2-4 ; 19:1-20 ), the menstruating woman ( Lev 15:19-24 ), the handling of the ashes of the red cow or the Day of Atonement offerings ( Leviticus 16:26 Leviticus 16:28 ; Num 19:7-10 ), emission of semen ( Lev 15:16-18 ), contamination by a carcass ( Levv 11:24-40 ; 22:5 ), and secondary contamination ( Lev 15 ; 22:4-7 ; Num 19:21-22 ).
Purification always involved waiting a period of time (until evening for minor cases, eighty days for the birth of a daughter), and could also involve ritual washings symbolizing cleansing, atoning sacrifices, and priestly rituals. "Unclean" objects required purification by water (wood, cloth, hide, sackcloth) or fire (metals), or were destroyed (clay pots, ovens), depending on the material ( Lev 11:32-35 ; Num 31:21-23 ).