What is hyssop? What was hyssop used for in the Bible?

from the old testament

• Hyssop first appears in the Bible in Exodus during the first Passover. The Israelites were preparing for the last plague that God would send upon Egypt, and Moses gave the Israelites instructions, saying "Go and select lambs for yourselves according to your clans, and kill the Passover lamb. Take a bunch of hyssop and dip it in the blood that is in the basin, and touch the lintel and the two doorposts with the blood that is in the basin. None of you shall go out of the door of his house until the morning" (Exodus 12:21–22). The hyssop helped paint the blood of the lamb on the doorpost. This blood served as protection for the Israelites, setting them apart from the unbelieving Egyptians. Passover is still celebrated by Jews today. God designed Passover to be a way to remember what He had done for the Israelites and to foreshadow the Messiah. It is filled with images of Jesus Christ, who is the Messiah.
• Hyssop is also mentioned in Leviticus 14:6 for sprinkling blood in the cleansing ceremony for a leper.
• Hyssop is used in Numbers 19:1–10 along with other ingredients to be thrown into the fire that is burning a heifer that has been sacrificed. The ashes were to be deposited in a clean place outside the camp and "kept for the water for impurity for the congregation of the people of Israel" (Numbers 19:9). Numbers 19:17–18 talks about adding fresh water to the ashes of the sin offering and using hyssop to sprinkle the water on the tent where a person has died and on all who have touched the dead person. We see, then, that hyssop is linked to ceremonial cleansing.
• King David used hyssop as a symbol for spiritual purification in his psalm of repentance. He sings, "Against you, you only, have I sinned and done what is evil in your sight, so that you may be justified in your words and blameless in your judgment. … Purge me with hyssop, and I shall be clean; wash me, and I shall be whiter than snow" (Psalm 51:4, 7). David realized that he needed to be cleansed of his uncleanness inside and out. He called upon God to cleanse his adulterous heart, using the ceremonially purifying hyssop as a metaphor for his inward cleansing.

from the new testament

• After Jesus sustained beatings, humiliation, and excruciating pain, Jesus said, "I thirst" (John 19:28). While Christ hung on the cross, laden with our sins because He loves us, He was given wine on a branch of hyssop (John 19:29–30). Much like the first Passover, when hyssop was used to spread the purifying blood of the lamb upon the Israelites' doorposts, hyssop is used as Jesus bleeds out the blood that would purify and atone for our sins for eternity.

implications for today

Just as hyssop aided in spreading the blood of a sacrificial life to save the Israelites at the first Passover, hyssop aided in the shedding of Jesus' blood at the cross to save the world from their sins. This last use of hyssop at the cross eradicated the need for its ceremonial use of purification. Jesus' sacrifice upon the cross is the only purification we need to be right with God and live with Him for eternity. Hyssop was necessary in the Old Testament for purification, but Jesus' work on the cross has eliminated the need for ceremonial cleansing. His blood purifies all who believe in Him by faith once and for all, so that we no longer need to be cleansed ceremonially (Hebrews 10:1–23).

Hebrews 9:12–15 explains, "He entered once for all into the holy places, not by means of the blood of goats and calves but by means of his own blood, thus securing an eternal redemption. For if the blood of goats and bulls, and the sprinkling of defiled persons with the ashes of a heifer, sanctify for the purification of the flesh, how much more will the blood of Christ, who through the eternal Spirit offered himself without blemish to God, purify our conscience from dead works to serve the living God. Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred that redeems them from the transgressions committed under the first covenant." Cleansing can be found in Jesus Christ.