Read John 18 today.

John 18:15-18, 25-27 NLT[15] Simon Peter followed Jesus, as did another of the disciples. That other disciple was acquainted with the high priest, so he was allowed to enter the high priest’s courtyard with Jesus. [16] Peter had to stay outside the gate. Then the disciple who knew the high priest spoke to the woman watching at the gate, and she let Peter in. [17] The woman asked Peter, “You’re not one of that man’s disciples, are you?” “No,” he said, “I am not.” [18] Because it was cold, the household servants and the guards had made a charcoal fire. They stood around it, warming themselves, and Peter stood with them, warming himself.
[25] Meanwhile, as Simon Peter was standing by the fire warming himself, they asked him again, “You’re not one of his disciples, are you?” He denied it, saying, “No, I am not.” [26] But one of the household slaves of the high priest, a relative of the man whose ear Peter had cut off, asked, “Didn’t I see you out there in the olive grove with Jesus?” [27] Again Peter denied it. And immediately a rooster crowed.
We know that Jesus warned Peter about what was to come. Peter emphatically denied that that he would ever deny Jesus. Even when Jesus gave Peter forewarning, he was not prepared. Peter never saw it coming. This is the way it is with all of us. If we are honest, we all have moments of denial, moments of surprising sinfulness we never see coming. There are two thoughts I have as I think of this.
The first is the definition of spiritual maturity shared by one of my professors in seminary. He argued that spiritual maturity is not something that is measured one person compared to another, but but rather it is measured by how you respond to your own sinfulness today compared with yesterday. Consider how much time it takes from when you become aware of your sin until it grieves your heart. As that time decreases, you are becoming more mature. Full maturity is when we begin to give before we actually sin, and can therefore avoid it.
The second is the response of Jesus to Peter’s denial. Beforehand, Jesus sought to help Peter avoid it. Afterward, Jesus response was one of forgiveness and love. Before and after, Jesus was for Peter, Jesus was on Peter’s side. This is true for us as well.
How do you see yourself against the backdrop of Peter’s denial of Jesus? What can you learn about yourself? What can you learn about Jesus?