Then Peter remembered the word that Jesus had spoken: "Before the cock crows you will deny me three times." He went out and began to weep bitterly. Matthew 26: 69-75
When Jesus first met Peter, He fixed his gaze upon him and said, 'You are Simon, son of John; you will be called Peter'. (John 1:42)That was an experience of the grace of God in giving the fisherman a new vocation to proclaim the love and mercy of God.
Later on, Peter had a unique experience of grace with James and John when they witnessed the Transfiguration whereby the body of Jesus was transformed by Light. Matthew 17:1-13
Despite experiencing miracles, healings and the Transfiguration, Peter was still full of fear of death and therefore denied knowing Jesus in the courtyard. Read on: https://susannetimpani.blogspot.com.au/