Acts 8:36-38

And as they continued along on the way, they came to some water, and the eunuch exclaimed, See, [here is] water! What is to hinder my being baptized? And Philip said, If you believe with all your heart [if you have a conviction, full of joyful trust, that Jesus is the Messiah and accept Him as the Author of your salvation in the kingdom of God, giving Him your obedience, then] you may. And he replied, I do believe that Jesus Christ is the Son of God. And he ordered that the chariot be stopped; and both Philip and the eunuch went down into the water, and [Philip] baptized him.