Baptism is one of two sacraments. A sacrament means a sign and a seal of God's promise over God's people. As a sign it points to the washing away of your sin. As a seal it marks you as a member of God's covenant family. In the New Testament of the Bible, baptism takes the place of circumcision as the sign and seal of God's people (Colossians 2:9-15). We baptize children into God's family on the basis of Mom and/or Dad's faith (Acts 16:33). We baptize older kids and grown ups based on their own faith in Jesus (Acts 2:36-38).
Find out more about what Presbyterians believe.