John of Damascus — on Lev 14:8 (ORTHODOX FAITH 4.9)

“A first baptism was that of the flood [of Noah] that cut away of sin. A second was that by the [Red] Sea and the cloud, for the cloud is a symbol of the Spirit, while the sea is a symbol of the water. A third is that of the [Levitical] law, for every unclean person washed himself with water and also washed his garments and thus entered into the camp. A fourth is that of John, which was an introductory baptism leading those thus baptized to penance, so that they might believe in Christ.”