What does Acts 8:13 mean?

Philip, a Jesus-follower and one of the first deacons of the church, has fled Jerusalem because of growing persecution (Acts 6:1–6; 8:1–5). He has come north to Samaria and preaches the good news about salvation through Jesus to the Samaritans. To authenticate his teaching, the Holy Spirit empowers him to expel demons and heal the paralyzed and lame (Acts 8:7). In response, the people believe every word and the city is filled with joy (Acts 8:8).

But Philip is not the only person in town with supernatural abilities. A man named Simon has entranced the people for some time with his magic (Acts 8:9–10). The difference is that Philip's miracles are signs. They specifically indicate that his power is from God, not demons—the only other source of supernatural power. Philip's power is so great, even Simon believes. But what does he believe?

One Passover in Jerusalem, Jesus dealt with a similar situation. "Many believed in his name when they saw the signs that he was doing" (John 2:23), but Jesus knew their understanding was incomplete. They may have believed He was the Messiah, but they didn't know who the Messiah truly was and what He had come to do. Another time, after He fed the five thousand, the people declared Him to be the Prophet whom Moses had promised. But Jesus knew they weren't interested in the submission and repentance that would reconcile them to God; they wanted to make Him king because He could feed them (John 6:14–15, 26–27).

James explains that there is a difference between "belief" and the faith that leads to salvation (James 2:19). Even though Simon is baptized, his approach to God, spirituality, and obedience (Acts 8:18–19) suggest he might not have a truly saving faith.