In Acts chapter 8, is one of the great examples of a person being converted that we can read about in the New Testament. There are three involved in this story of the eunuch's salvation, the Holy Spirit, Philip the preacher, and the Ethiopian who was riding in his chariot reading from prophet Esaias.
Many today claim one is saved by a direct operation of the Holy Spirit upon their lives. And if that be true, then there was no better opportunity for the Holy Spirit to do that here, upon the eunuch. The Holy Spirit was in the area! But the Holy Spirit sent Philip the preacher to preach the word. The reason he sent the preacher is because it is in accordance with God's plan. We find God's plan in Mark 16:15,16, "Go ye into all the world, and preach the gospel to every creature. He that believeth and is baptized shall be saved, but he that believeth not shall be dammed". Also Rom. 1:16 says the gospel "is the power of God unto salvation". God's plan is for man to be saved, through obeying the gospel. That is why the Holy Spirit sent the preacher. The eunuch needed to hear the word of God, and he needed to obey that word also. Remember "faith cometh by hearing, and hearing by the word of God" .
In this story we have Philip being told by the Holy Spirit to join himself to the chariot and in verse 35 of Acts 8 it says Philip "preached unto him Jesus". To preach Jesus is to preach Jesus' words, i.e., the gospel, which is the Good News. And the reason the eunuch realized the need to be baptized, is that when one preaches Jesus, he preaches "he that believeth and is baptized shall be saved", Jesus' own words.
If just only believe in Jesus is all man must do, this would been a good time to tell it. If just receive Jesus into your heart and pray for forgiveness is all a man must do, this would been a good time to tell it. Quite a difference in what many modern day preachers are telling people to do for salvation as compared to what the Bible says, isn't it!
So in Acts 8:36 the eunuch asked, "See, here is water, what doeth hinder me to be baptized" If all preachers today would preach the truth as Philip did, then all hearers would see the need to be baptized like the eunuch.
Philip's answer to the eunuch's question, verse 37 was, "If thou believest with all thine heart, thou mayest." The eunuch said, "I believe that Jesus Christ is the Son of God." Those who baptized infants do not follow this example do they?
In verse 38 Phillip "baptized him." The eunuch believed and was baptized, and that's doing exactly what Jesus commanded in Mark 16:16, "He that believeth and is baptized shall be saved."
How about you, have you been baptized for the remission of sins? Were you told to do the same thing to be saved as the eunuch was? If you have never been baptized or was baptized for some other reason than for the forgiveness sins, then as Ananias told Saul in Acts 22:16, "why tarriest thou? Arise, and be baptized, and wash away thy sins".