Locke continues. Hyssop was used to sprinkle consecrated water on healed lepers as a rite of purification. (Leviticus 14:3-8). Locke takes this as analogy: as the priest cleansed the leper, So David pleaded for his guilt to be removed, and so Locke looks to Christ for his mercy

Purify me with hyssop, and I shall be clean;
Wash me, and I shall be whiter than snow.

Psalm 51:7, NASB
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With swete Hysope besprinkle thou my sprite:
Not such hysope, nor so besprinkle me,
As law vnperfect shade of perfect lyght
Did vse as an apointed signe to be
Foreshewing figure of thy grace behight.
With death and bloodshed of thine only sonne,
The swete hysope, cleanse me defyled wyght,
Sprinkle my soule. And when thou so haste done,
Bedeawd with droppes of mercy and of grace,
I shalbe cleane as cleansed of my synne.
Ah wash me, Lord: for I am foule alas:
That only canst, Lord, wash me well within,
Wash me, O Lord: when I am washed soe,
I shalbe whiter than the whitest snowe.

Anne Locke, Meditations of a Penitent Sinned.
Photo by Stefan Kunze on Unsplash