It is amazing that God promises blessings like forgiveness of sins (Acts 2:38,39) and eternal life (1 Peter 3:21) from the action of water in baptism touching a person. You might think that the water must somehow be special, almost magical.
But the water used in baptism is just simple water. There’s nothing special about it in and of itself, even when it has been put to the holy use of baptism. It’s not magical or holy.
When the water is used the way God tells us to use it (Matthew 28:19), however, it is the Word of God that makes the water a washing of rebirth by the Holy Spirit (Titus 3:5). The Word of God is what God says. When God talks, powerful things happen (Genesis 1:3). When he promises something, he means it and it happens (Ephesians 5:25,26).
So when we say that the water of baptism connects us to Jesus Christ (Galatians 3:27), we are talking about the special promises of God that turn simple water into water used by God’s command and connected with God’s Word.
God promises forgiveness of sins and eternal life through faith in him (John 3:16). Baptism does not replace that clear promise. Instead, it applies that clear promise to individuals (Mark 16:16). Baptized people never have to question whether God’s promises apply also to them. They’re baptized, and water, tangible and verifiable, makes that clear and certain.
Old Testament priests washed themselves at a large basin in the Temple in Jerusalem before God declared them ceremonially clean to serve Him. Today God washes us in baptism and declares us ceremonially clean to serve him through the resurrection of Jesus Christ (1 Peter 3:21).
It’s simple water, but it does great things in baptism.