Leviticus 14:4 - Joseph Benson’s Commentary on the Old and New Testaments

Two birds The one to represent Christ as dying for his sins, the other to represent him as rising again for his purification or justification. Alive and clean Allowed for food and for sacrifice. Cedar-wood A stick of cedar, to which the hyssop and one of the birds were tied by the scarlet thread. Cedar seems to be chosen, to denote that the leper was now freed from that corruption which his leprosy had brought upon him, that kind of wood being in a manner incorruptible. Scarlet A thread of wool of a scarlet colour, to represent both the leper's sinfulness, and the blood of Christ, and the happy change of the leper's colour and complexion, which before was wan and loathsome, now sprightly and beautiful. Hyssop The fragrant smell of which signified the cure of the leper's ill scent.