Acts 8:13

And Simon also himself believed

(Hο δε Σιμων κα αυτος επιστευσεν). Note the same verb in the aorist tense επιστευσεν. What did he believe? Evidently that Jesus was this "power of God" not himself (Simon). He saw that the miracles wrought by Philip in the name of Christ were genuine while he knew that his own were frauds. He wanted this power that Philip had to add to his own pretensions. "He was probably half victim of self-delusion, half conscious impostor" (Furneaux). He was determined to get this new "power," but had no sense of personal need of Jesus as Saviour for his sins. So he submitted to baptism (βαπτισθεις, first aorist passive participle of βαπτιζω), clear proof that baptism does not convey salvation.He continued with Philip

(ην προσκαρτερων τω Φιλιππω). Periphrastic imperfect of the verb προσκαρτερεω (see on Acts 2:46). He stuck to Philip (dative case) to find out the secret of his power.Beholding

(θεωρων). Watching the signs and miracles (powers, δυναμεις that threw his "power" in the shade) as they were wrought (γινομενας, present middle participle of γινομα). The more he watched the more the wonder grew (εξιστατο). He had "amazed" (verse Acts 8:9) the people by his tricks and he was himself more "amazed" than they by Philip's deeds.