In Acts 8:18, we begin to see what’s behind the curtain of the façade of Simon’s false profession. He did not come to Christ because he was desperate for forgiveness of sins and an external righteousness to be given to him—those being the only marks of true conversion with no exceptions. No, he accepted the message because everyone else was doing it and he was in awe of a superior power than what he had–“So how much for that authority, Peter? I became great and wealthy before; the sky is the limit with what I could do for myself with this kind of power!” He wanted power in order to take respect and money from people instead to bless others like the apostles did. So in vv.20-22 Peter essentially tells him “you will perish if you do not repent from this wickedness because your heart is not right with God!”
Then in v.23, Peter gives some insight into Simon’s heart, which can be summarized in this way—Simon had never repented of his greatest idolatry. All he repented of was having a lesser power. His heart was saying: “I’ll get on board with this thing called Christianity as long as I don’t have to give up my pursuit to be great.” But someone might object—“Didn’t Simon believe and get baptized just like the other Samaritans?” Yes, but the Bible clearly teaches a category of false faith—John portrays this throughout his gospel; James speaks of a dead faith that is comprised of just mere words and 1st John was written to expose false professors. Simon’s spiritual state should not be a surprise, given what was his life’s primary pursuit.
So in the end, what does it matter if someone makes a profession of Christ if what was ruling their hearts beforehand is still ruling their heart afterwards? Evangelicalism has created a gospel message that allows Simons to infiltrate and permeate the church. We don’t call people to die to themselves in order to have new life in Christ; we call people to find their purpose and attend church services. This text exposes the absurdity of categorizing everyone as either churched vs. unchurched. Simon was churched! He was following Philip around everywhere.!
Listen to the stark contrast to this church/unchurched category in the following texts—Gal. 2:20 I have been crucified with Christ; and it is no longer I who live, but Christ lives in me; and the life which I now live in the flesh I live by faith in the Son of God, who loved me and gave Himself up for me...2 Cor. 5:14 For the love of Christ controls us, having concluded this, that one died for all, therefore all died; 15 and He died for all, so that they who live might no longer live for themselves, but for Him who died and rose again on their behalf.
The death of self and a life lived set apart unto God is what matters and that’s why Peter goes after this issue with Simon. He doesn’t care that Simon wanted to attach himself to the church and loved to follow Philip around because he thought he did amazing things. He cared about the truth and about Simon’s soul, pertaining to the prospect of Simon facing the judgment of God, which is why he spoke to him like he did. In other words, he spoke the truth in love.