The New City Catechism Question 44: What is Baptism?

Answer: Baptism is the washing with water in the name of the Father, the Son, and the Holy Spirit; it signifies and seals our adoption into Christ, our cleansing from sin, and our commitment to belong to the Lord and to his church.

Scripture: Matthew 28:19
Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit. . . .