Many would object to baptism as being necessary for salvation, saying it is a work.  Baptism is most certainly a work – it is a work of God (Colossians 2:12).  When a person is baptized, God saves him from his sins (Mark 16:15-16, Titus 3:5, I Peter 3:21), washes his sins away (Acts 22:16), places that person into the body of Christ (I Corinthians 12:13) – that body is the church of Christ (Ephesians 1:23, Romans 16:16).  When a person is baptized, God is busy at work, saving that person from his sins, washing his sins away, and adding him to his church!  Baptism is the point at which we submit to God’s will and let Him work on us!