An herb fit for cleansing. David [says]: "you will cleanse me with hyssop, and I will be purified." For it was effecting no forgiveness of sins, but it indicates a certain figure. Sprinkling the blood of a sheep [mixed] with hyssop onto the doorposts they used to escape the hands of the destroyer. And those things [are] an exemplar of sufferings bringing deliverance: for here [is] blood, and a timber, [sc. signifying] salvation.[1]