Psalms 51:7

“Purge me with hyssop, etc.] Or “thou shalt purge me with hyssop” ; or “expiate me”; which was used in sprinkling the blood of the paschal lamb on the door posts of the Israelites in Egypt, that the destroying angel might pass over them, (<021222>Exodus 12:22,23); and in the cleansing of the leper, (<031404>Leviticus 14:4-7); and in the purification of one that was unclean by the touch of a dead body, etc. (<041906>Numbers 19:6,18); which the Targum on the text has respect to; and this petition of the psalmist shows that he saw himself a guilty creature, and in danger of the destroying angel, and a filthy creature like the leper, and deserving to be excluded from the society of the saints,…”

“A series of prayers for forgiveness and purifying. Purge . . . hyssop--The use of this plant in the ritual (Exo 12:22; Num 19:6, Num 19:18) suggests the idea of atonement as prominent here; "purge" refers to vicarious satisfaction (Num 19:17-20).”

“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, Lev 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…”

“Hyssop - As lepers, are by thy appointment purified by the use of hyssop and other things, so do thou cleanse me a leprous and polluted creature, by thy grace, and by that blood of Christ, which is signified by those ceremonial usages. Psalms 51:8”

“51:7 Purify me from my sins (literally Purify me with the hyssop branch; see Exod 12:22; Lev 14:4; John 19:29; Heb 9:19): The psalmist depends on God to purify and renew him (see Isa 1:18).”

“Purge: Lev 14:4-7, Lev 14:49-52; Num 19:18-20; Heb 9:19 and: Heb 9:13, Heb 9:14; Jo1 1:7; Rev 1:5 whiter: Isa 1:18; Eph 5:26, Eph 5:27; Rev 7:13, Rev 7:14 Psalms 51:8”

“The possession of all possessions, however, most needed by him, the foundation of all other possessions, is the assurance of the forgiveness of his sins. The second futures in Psa 51:9 are consequents of the first, which are used as optatives. Psa 51:9 recalls to mind the sprinkling of the leper, and of one unclean by reason of his contact with a dead body, by means of the bunch of hyssop (Lev. 14, Num. 19), the βοτάνη καθαρτική (Bhr, Symbol. ii. 503); and Psa 51:9 recalls the washings which, according to priestly directions, the unclean person in all cases of uncleanness had to undergo. Purification and washing which the Law enjoins, are regarded in connection with the idea implied in…”