Many have defined baptism as an outward sign of an inward work that the Lord has done.

The meaning of inward works or experiences is conveyed to the mind only by means of outward signs, figures or symbols. Therefore, if you do not understand the meaning of baptism, you will only dimly understand its inward importance. Later you will mature beyond the point of needing symbols or visual helps for comprehension, but you should not forget that those symbols were quite necessary in the early days of growth and learning. Just as the Lord’s Supper or communion is a constant reminder of Christ’s work of redemption, so baptism is a lifelong reminder of Christ’s redeeming work in the life of a believer. Baptism is administered only once to the believer in the Christian lifetime. Yet every time we witness another person being baptized, it is once again a reminder to all present of our death, burial and resurrection together with Christ, by which we gained admittance into the Kingdom of God.

Because Christ commanded it. “Therefore, go and make disciples of all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Spirit, and teaching them to obey everything I have commanded you.” Matthew 28:19-20

Baptisms do not make you a believer—it shows that you already believe. Baptism does not “save” you, only your faith in Christ does that.

Martin Luther: “I would have those who are to be baptized to be entirely immersed, as the word imports and the mystery signifies.”

Every person who has believed in Christ. “Those who believed and accepted his message were baptized.” Acts 2:41

As soon as you believe. “Those who believed…were baptized…that day!” Acts 2:41 and Acts 8:35-38