We are never told what went on in the apostles’ minds whenever they were facing obstacles. What we are told is how they acted and spoke.
When Jesus was being led away and eventually questioned and tortured, Peter followed but when asked by others, he denied even knowing Jesus. We aren’t given the details of what Peter was thinking, but his actions gave it all away. He was terrified and full of doubt. So much so that when people recognized him as a follower of Jesus, he strongly denied in order to keep himself “safe”. The change in Peter came when he saw Jesus after His resurrection. Peter never denied Him again. When He told Jesus he loved Him, and Jesus told him to “Feed His lambs”, that’s exactly what Peter went out and did until He died. He stood in front of authorities and told about Jesus’ power and resurrection. Urging everyone to repent and have faith in the only true God and Savior.
I think what happened is he finally realized the truth, that nothing on earth, no person or creature or circumstance could take him away from Jesus. Jesus was the only one who gave him peace and confidence. Jesus gave Peter vision. The vision of what truth actually is, that our spirits are what is real and will live forever (something we can’t fathom while we are in our earthly bodies). Where our spirits will live forever depends on what we learn and believe here on earth.
If we have doubts about our circumstances, then we have doubts about the power of Jesus and His resurrection. What I mean is, we rely too much on our own power to let it go and let Jesus intercede for us. What’s incredible is that when we do let go, the power that Jesus exhibits through us is beyond anything we could have ever even thought of doing. The whole point is to let it all point back to Him, not to us.
When will we ever get that through our thick skulls?
That’s what the apostles did. They quit letting their thoughts get in the way of their actions. You know those doubts kept creeping into their thoughts, but they immediately turned their focus on what they had seen Jesus do in their lives and were able to show faith to everyone around them. They spoke His Word and trusted in Him to perform whatever His will was, and STILL be happy!
If God told you not to quit, then you MUST keep your focus on HIM and let HIM do the work. He will tell you what to do if you keep your heart open to HIM. Your whole life will be a witness to God’s incredible power when you do that and the peace that you crave will be right there with you at all times. The doubt in your minds will not be shown in your actions. After all, actions speak louder than words.