There are several examples from the Bible proving that failure is not fatal.
Peter is a prime example. He denied the Lord – not just once but three times. Jesus warned Peter this would happen. Yet Peter trusted in his own strength and proclaimed he would never deny the Lord. A few hours later that is just what happened. Jesus overheard Peter’s third denial, turned and looked at him. Peter went out and wept bitterly, sorry for what he had done (Luke 22:61-62).
Peter needed to know he was forgiven. The day of Jesus’s resurrection three women found His tomb empty. An angel, appearing as a young man, told the women that Jesus was risen “But go your way tell his disciples and Peter…” Mark 16:7. Weeks later on the shore of Galilee, Jesus asked Peter three times, “Do you love me?” (corresponding to the three times he denied the Lord). Each time Peter said, “Yes, you know I love you.” (John chapter 21) Jesus gave Peter work to do for him. “Feed my lambs.”
Peter faithfully carried out that responsibility. He was the major speaker on the day of Pentecost (Acts, chapter 2), spoke boldly in the temple (Acts, chapter 3), and was used to bring the Gospel to the first Gentile convert, Cornelius (Acts, chapter 10).
David is another one whose failure was not fatal. After many years as a faithful king, somehow his heart and conscience had went to sleep. He committed adultery with Bathsheba and had her husband, Uriah, purposely killed in battle. Once brought to his attention, David realized he sinned.
The Lord forgave him. According to the law, He should have been put to death. But the Lord dealt with him according to his faith and sincere repentance. He received some punishment for his sins, but he had the Lord’s forgiveness. (See 2 Samuel chapters 11 and 12.) Psalm 51 was written during this experience. It expresses David’s attitude. NKJV – “Create in me a clean heart, O God, And renew a steadfast spirit within me.” Psalm 51:10-11 (NKJV)
God showed His forgiveness by continuing to honor His promise that David’s descendants would always be on the throne. Additionally, David was given the opportunity to prepare the materials for the Temple built by his son Solomon.
Both Peter and David show the proper attitude to turn a failure into a victory. They humbled themselves and sincerely prayed to God asking forgiveness. They cleansed their heart from any wrong spirit. Their inmost desire was to be pleasing to God.
The Lord expressed His forgiveness by giving them an opportunity to serve Him. In Peter’s case it was in sharing the Gospel message. In David’s case it was continuing on the throne and preparing the materials for the Temple.