The exact botanical species of "hyssop" has not yet been determined. The plant was used in purification rites at the time of Passover (Exod. 12.22), for the purification of lepers (Lev. 14.4, 6), and after the plague (Lev. 14.49-52), as well as during the sacrifice of a red heifer (Num. 19.2-6). In these instances, the hyssop used was probably a variety of marjoram. King David referred to hyssop in ritual purification in Psalm 51.7: "Purge me with hyssop, and I shall be clean: wash me, and I shall be whiter than snow."
The hyssop plant used at the crucifixion of Jesus was probably a cornstalk type of plant that grew in the vicinity to about a height of six feet. A sponge soaked in vinegar and tied onto the end of the hyssop stalk was held up to Jesus' mouth when he cried out, "I thirst" Uohn 19.29).