A person can become pure again by repenting and returning to God.
In the Holy Quran, it is mentioned that human beings can return to God and be purified. Allah's mercy is vast, and in Surah Az-Zumar, verse 53, He says: "O My servants who have believed, fear your Lord. For those who do good in this world is good, and the earth of Allah is spacious. Indeed, the patient will be given their reward without account." This verse demonstrates that no matter how much a person may have sinned in the past, if they turn back and repent for their sins, Allah will forgive them, and they can become pure again. Additionally, in Surah An-Nasr, verse 3, it is stated: "And glorify the praise of your Lord and ask for His forgiveness. Indeed, He is ever Accepting of Repentance." In this verse, Allah invites humans to turn to Him with supplication and to seek forgiveness. Moreover, the Quran recounts the stories of several prophets who, after committing sins and disobedience, returned to Allah and repented. An example is the story of Prophet Jonah (A), who, after being in the belly of the fish and repenting, returned to God. Therefore, Quranic verses clearly illustrate that every human has the opportunity to purify themselves and repent, and Allah is always ready to forgive and grant them a fresh start.
O My servants who have believed, fear your Lord. For those who do good in this world is good, and the earth of Allah is spacious.
And glorify the praise of your Lord and ask for His forgiveness. Indeed, He is ever Accepting of Repentance.
Once, a man named Ali approached a sage with a question in his mind: "Can I be pure again?" The sage smiled and said, "Yes, every person can return to God with sincerity and repentance. Remember the story of Jonah (A); when he was in the belly of the fish, he repented to God, and Allah saved him." Ali returned home with hope and faith.