WOOL
The hair of sheep and other animals. That of the sheep was used for spinning and weaving, and is what is generally known as wool.
In the figurative language of Isaiah 1:18, the white wool represents the state resulting from Jehovah’s removal of the people’s sin.
Sin, for its part, is compared to wool dyed scarlet.
The Law prohibited wearing clothing made of a mixture of linen and wool: it is an unnatural mixture, a type of the contrary work of the Spirit and the flesh in the Christian (Lev. 19:19; Deut. 22:11).