Purge me with hyssop, and I shall be clean - On the word hyssop, see the notes at John 19:29; notes at Hebrews 9:19. The plant or herb was much used by the Hebrews in their sacred purifications and sprinklings: Exodus 12:22; Leviticus 14:4, Leviticus 14:6, Leviticus 14:49, Leviticus 14:51; 1 Kings 4:33. Under this name the Hebrews seem to have comprised not only the common “hyssop” of the shops, but also other aromatic plants, as mint, wild marjoram, etc. - Gesenius, “Lexicon” The idea of the psalmist here evidently is not that the mere sprinkling with hyssop would make him clean; but he prays for that cleansing of which the sprinkling with hyssop was an emblem, or which was designed to be represented by that. The whole structure of the psalm implies that he was seeking an “internal” change, and that he did not depend
