In the contemporary world “baptism” is one of those loaded religious words. For most people, when they think of baptism they think of a nice church ritual, water, white robes and celebration. In the first century, however, “baptism” was not a nice religious word. Quite the opposite, “baptism” was a violent word. There seems an inherent connection between the word “Baptism” and violence. So, it seems that the early church used the word “baptism” to refer to an act of washing as the initiation into the eschatological kingdom of God that was inaugurated by the death and resurrection of Jesus.
Josephus uses the verb “baptize” to describe ships sinking in battles or raging storms (JW 2.556; 3.368, 423, 525; Ant. 9.212; Life 1.15). Other times he uses the word to refer to someone drowning or a sword being plunged into someone’s stomach (JW 1.437; 3.423, 525; Ant. 15.55; JW 2.467)! In fact, only once in Josephus does the verb refer to a cleansing ritual (Ant 4.81). The verb βαπτίζω occurs only four times in the LXX (2 Kgs 5.14; Isa 21.4; Jdt 12.7; Sir 34.25). Three of these four references describe purifying washings (2 Kgs 5.14; Jdt 12.7; Sir 34.25). The reference in Isaiah however is consistent with the violent connotation of the word in Josephus. In a prophetic oracle describing the fall of Babylon, Isaiah writes, “My heart staggers; horror has appalled me; the twilight I longed for has been turned for me into trembling” (21.4 ESV). In place of “horror has appalled me” the LXX reads “evil engulfs me” ἡ ἀνομία με βαπτίζει. Here the LXX translator picks up on the violent connotation associated with this word.
Baptism is associated with a violent plunge, but it is also used to describing an immersion for cleansing. So it is not surprising that baptism can be used as a metaphor for violence done to Jesus at the crucifixion (Mk 10:38–39; Lk 12:50) as well as an initiation ritual for the forgiveness of sins (Acts 2.38; 22.16). It only makes sense that this violent word describes the initiation of Christians into the eschatological kingdom of God. Just as the violence done to Jesus initiated the eschatological kingdom so baptism initiates the Christian into that kingdom. Unlike circumcision which is limited to the male Israelite, initiation into the eschatological kingdom is through baptism. Thus, “For all of you who were baptized into Christ have clothed yourselves with Christ. There is neither Jew nor Greek, slave nor free, male nor female, for you are all one in Christ Jesus. If you belong to Christ, then you are Abraham’s seed, and heirs according to the promise” (Gal 3.27–29 NIV). We don't have to be male or female, Jew or Gentile, we just have to die to ourselves and live for Christ.