Hyssop returns at the death of Jesus: in John's Gospel the sponge of sour wine is raised to his lips on a stalk of hyssop, tying the herb of the Passover to the Passion. In Christian tradition hyssop accordingly became an emblem of penitence, humility and purification, and sprigs of it were used to sprinkle holy water in the rite of aspersion. The garden hyssop is a warm, camphor-scented shrublet of the mint family, a bee-plant and a strewing herb; Culpeper placed it under Jupiter. Its meanings, across Jewish and Christian usage alike, gather around one idea, the washing away of defilement and the making clean of what was stained.
The Latin rite of aspersion took its very words from the Psalm: the priest, sprinkling the congregation with holy water, traditionally sang Asperges me hyssopo et mundabor, purge me with hyssop and I shall be cleansed, tying the Hebrew Passover herb directly into Catholic liturgical practice that continues in some parishes today, a rare case of the same word and the same plant crossing more than three thousand years and two religious traditions without a break. The essential oil of garden hyssop, genuinely rich in pinocamphone, is regarded by modern aromatherapists as one of the more potent and, in overuse, potentially irritating essential oils, a chemical footnote quite separate from the biblical plant's ceremonial history but worth noting as a plain caution for anyone using the modern herb rather than its ancient, probably different, namesake.