Towards mutual understanding:
Everyone agrees that Baptism is a sign. The London Baptist Confession lists baptism as signing: “death and resurrection; of his being engrafted into him; of remission of sins; and of giving up into God, through Jesus Christ, to live and walk in newness of life.” The Westminster Confession adds “a sign and seal of the covenant of grace” and “of regeneration” to that list. Each time baptism is performed, often all those items are not visited, but certain signs may be communicated by the very mode of baptism. Traditions will use different modes, and each communicates a different truth about the sign of baptism. Before those practicing other modes dismiss immersion, they should understand the biblical image communicated therein. Also, those practicing immersion should understand the biblical images communicated in pouring and sprinkling:
Immersion is the exclusive mode of baptism for Baptists and certain Orthodox. The image communicated is one of burial and resurrection with Christ. (Col 2:12) The image here communicates a wonderful picture of repentence, turning from sin that once was sweet, and now is bitter to Christ who is now sweeter. Such pictures can help the Christian know the inseparable relationship between faith and repentance in the death and rising, just as Romans 6:4 says:
“We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life.”
Many other traditions, including Anabaptists, Roman Catholics, Lutherans, Reformed and others will allow pouring as a mode of baptism. This mode was also used in the early church, as evidenced in the early church manual the Didache, (7.3) a document perhaps as old as the New Testament writings. The image here communicated is one of pouring out of the Spirit.
The book of John uses the image of water for the Spirit throughout the book, explicitly stated as such in 7:38-39. In Titus, God is said to wash us (using the word for washing associated with baptism in Acts 22:16) saying God saved us, “by the washing of regeneration and renewal of the Holy Spirit, whom he poured out on us richly.” (Titus 3:5-6) Images of the pouring out of the Holy Spirit also exist in Acts 2:17-18, 33.
Other Reformation traditions will use sprinkling as a mode of baptism. Leviticus 16 instructs the priest to sprinkle blood on the mercy seat on the ark of the covenant to “make atonement for the Holy Place,” becoming a perfect type of Christ’s atonement, where he acted both as High Priest and as the sacrifice. When making this connection with the mercy seat in Hebrew 9, the explicit identification of baptism with sprinkling is made in Hebrews 9:10, 13.