Purge me with hyssop, and I shall be clean: wash me, and I shall be whiter than snow.–Psa 51:7) )

In the Hebrew language there are two words to express the different kinds of washing, and they are always used with the strictest propriety; the one, to signify that kind of washing which pervades the substance of the thing washed, and cleanses it thoroughly; and the other to express that kind of washing which only cleanses the surface of a substance which the water cannot penetrate. The former is applied to the washing of clothes; the latter is used for washing some part of the body. By a beautiful and strong metaphor, David uses the former word in this and the second verse: "Wash me thoroughly from mine iniquity, and cleanse me from my sin;" "Wash me and I shall be whiter than snow." So in Jeremiah 4:14, the same word is applied to the heart. (O Jerusalem, wash thine heart from wickedness, that thou mayest be saved.)