Hyssop. Exodus 12:22. A plant often used in the ceremonies of purification. Leviticus 14:4, Leviticus 14:6, Leviticus 14:51, Psalms 51:7. One of its characteristics is referred to in 1 Kings 4:33. It is associated with our Saviours last hours. John 19:29. More than twenty different plants have been urged as the species intended. Tristram and other recent authorities favor the caper-bush. Dr. Post, of Syria, argues very conclusively in favor of a species of marjoram.