Anas (RAA) narrated that Allah's Messenger (Peace Be upon Him) said: "All the sons of Adam are sinners, but the best of sinners are those who repent often.” Related by At·Tirmidhi and Ibn Majah with a strong chain of narrators.
There is no one without a sin, flaw or guilt that he committed, but the best of people are those who wipe their sins by repentance. The Prophet (Peace Be upon Him) guided us to do so.
In the hadith narrated by Abu Bakr (May Allah be pleased with him), he said that he heard Allah's Messenger (Peace Be upon Him) saying: "There is no man who commits a sin, then stands for purification, then performs Salat, then seeks forgiveness from Allah, except that Allah forgives him. Then he recites this Ayah: '…those who remember God and implore forgiveness for their sins if they do something shameful or wrong themselves– who forgives sins but God?'" (Ali Imran: 135)