Wash me thoroughly. — Literally, Wash me much, whether we follow the Hebrew text or the Hebrew margin. The two clauses of the verse are not merely antithetic. The terms wash and cleanse seem to imply respectively the actual and the ceremonial purification, the former meaning literally to tread, describing the process of washing clothes (as blankets are washed to this day in Scotland) by trampling them with the feet, the latter used of the formal declaration of cleanliness by the priest in the case of leprosy (Leviticus 13:6-34). (For the iniquity and sin, see Psalms 32:1.)
Related Commentaries of Psalms 51:2
Psalms 51:2
2 Wash me throughly from mine iniquity, and cleanse me from my sin.