Psalms 51:7 References
a Exodus 12:22, Leviticus 14:4, Numbers 19:18, Hebrews 9:19
Exodus 12
22
"aYou shall take a bunch of hyssop and dip it in the blood which is in the basin, and apply some of the blood that is in the basin to the lintel and the two doorposts; and none of you shall go outside the door of his house until morning.
Leviticus 14
4
then the priest shall give orders to take two live clean birds and acedar wood and a scarlet string and hyssop for the one who is to be cleansed.
Numbers 19
18
'A clean person shall take hyssop and dip it in the water, and sprinkle it on the tent and on all the furnishings and on the persons who were there, and on the one who touched the bone or the one slain or the one dying naturally or the grave.