The gospels were written for sinners to know who to believe in.
Acts was written to show sinners exactly how to believe in Him...
38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
259. How is Baptism given?
Baptism is given by pouring water on the head of the child, saying at the same time these words: 'I baptise you in the name of the Father, and of the Son, and of the Holy Spirit'.
260. What do we promise in Baptism?
We promise in Baptism to renounce the devil and all his works and pomps.
261. Is Baptism necessary for salvation?
Baptism is necessary for salvation because Christ has said: 'Unless a man is born again through water and the Spirit, he cannot enter the kingdom of God'. (John 3:5)