Baptism. An ex-Muslim steps into the tomb with Jesus

"Baptism."
The word baptism never appears in the old testament. However, when John the Baptist came baptizing in Judea, a group of priests and Levites asked him, "Why do you baptize if you are not the Christ...?"
Why would they ask John such a question?

Let's look at just some of the many clues for baptism given to us in the old testament, and why this makes baptism essential!