1. God who made us clean with the blood of Christ, the Lamb of God (Ex 19:10)
    Rev 7:13-14, Isa 1:18

God had the Israelites sanctify their bodies and wash their clothes. (Ex 19:10)

Ex 19:10 And the Lord said unto Moses, Go unto the people, and sanctify them to day and to morrow, and let them wash their clothes,

In the Old Testament it was prophesied that God would cleanse us from our sins. (Isa 1:18)

Isa 1:18 Come now, and let us reason together, saith the Lord: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool.

The Lamb of God, Jesus shed His blood to cleanse us. (Rev 7:13-14)

Rev 7:13 And one of the elders answered, saying unto me, What are these which are arrayed in white robes? and whence came they?
14 And I said unto him, Sir, thou knowest. And he said to me, These are they which came out of great tribulation, and have washed their robes, and made them white in the blood of the Lamb.