Apostolic and authoritative, Paul tells us the concept of Christian Baptism refers to one idea of that rite. “One Baptism” means the concept of Christian Baptism has singular meaning. Since the reality of God’s mystery, Jesus, the types and figures of the Old Testament are fulfilled in this New age.
Israel was baptized into Moses in the cloud and the sea (1Cor. 10.2). This means the were protected by God through His presence in the cloud from their enemies-a key conceptual truth carrying over to this age. They were baptized in the sea signifying deliverance from death since when the Egyptians tried crossing, they were engulfed and died.
Baptism is a one-time observance for the Christian also and not to be repeated as seen in Jesus’ instruction to Peter at the Last Supper: “He who has bathed need only to wash his feet, and is completely clean” (John 13.10). This is regeneration (who has bathed) and is pictured by immersive baptism signifying dying to self and ‘all in’ with regard to being dedicated to Christ and His mission. The washing of the disciple’s feet and the subsequent teaching to wash one another’s feet refers to the restorative act of forgiving impulsive sins that occur in all Christians. Christians still sin but are new creatures in Christ along with having to old self still present and needing contention from the ‘New Person.’
The “One Baptism” is therefore a creedal stance of the believer where they identify themselves as united with Christ by performing a ritual picture in immersive baptism (the only kind there is). The one submitting to baptism is saying in essence: “I die to myself and henceforth rely on Jesus’ resurrection power to live a new life.”