Reviewing Peter’s growth through Christ is an interesting study, perhaps one that somewhat matches your own. Spiritual growth usually takes a circuitous path and while my experience with it is perhaps not as dramatic as Peter’s, it has been rocky at times nonetheless. Let’s take a very macro review.
In the beginning of his discipleship, it could seem that Peter was looking for a worldly material return from his decision to follow Jesus:
Mark 10:28–30 (ESV): 28 Peter began to say to him, “See, we have left everything and followed you.”
Now let’s jump to the point of Christ’s crucifixion. He boasted that he would stay true and fight for him even unto death. He meant so well, but he failed so miserably. When the moment came, a little girl’s question upset him, melted all his bravado, and he denied his Lord.
Next, let’s look how Peter’s life changed very dramatically with the endowment of the Holy Spirit. His boldness portrays a heart committed to Christ, even at his own peril:
Acts 4:8–12 (ESV): 8 Then Peter, filled with the Holy Spirit, said to them, “Rulers of the people and elders, 9 if we are being examined today concerning a good deed done to a crippled man, by what means this man has been healed, 10 let it be known to all of you and to all the people of Israel that by the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead—by him this man is standing before you well. 11 This Jesus is the stone that was rejected by you, the builders, which has become the cornerstone. 12 And there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved.”
When you have times where you feel unworthy of Christ’s atonement for your sins or are ashamed of something you have done, pray for forgiveness, worship with a grateful heart, and think about Peter’s growth. God loves you, wants to be close, and His Holy Spirit lives within you as a believer. Be bold.