To understand the significance of baptism, let's first consider its historical background. The Holman Bible Dictionary explains: "At some point close to the time of Jesus, Judaism began a heavy emphasis on ritual washings to cleanse from impurity. This goes back to priestly baths prior to offering sacrifices (Leviticus 16:4,24).
Probably shortly prior to the time of Jesus or contemporary with Him, Jews began baptizing gentile converts, though circumcision still remained the primary entrance rite into Judaism" (1991, "Baptism").