Read Qur’an: surahs, verses and hadiths

۞ قُلۡ يَٰعِبَادِيَ ٱلَّذِينَ أَسۡرَفُواْ عَلَىٰٓ أَنفُسِهِمۡ لَا تَقۡنَطُواْ مِن رَّحۡمَةِ ٱللَّهِۚ إِنَّ ٱللَّهَ يَغۡفِرُ ٱلذُّنُوبَ جَمِيعًاۚ إِنَّهُۥ هُوَ ٱلۡغَفُورُ ٱلرَّحِيمُ

Say [Allah says], “O My slaves who have transgressed against themselves, do not despair of Allah’s mercy, for indeed Allah forgives all sins[15]. He is indeed the All-Forgiving, the Most Merciful.

[15] It is for those who repent and correct themselves, no matter how big the sins are. The only unforgivable sin in Islam is dying in disbelief in Allah or associating others with Him. See 4:48. The Prophet (ﷺ) reports that Allah Almighty says, "O children of Adam! As long as you call upon Me, putting your hope in Me, I will forgive you for what you have done, and I will not mind. O children of Adam! If your sins were to reach the clouds of the sky and then you sought My forgiveness, I would forgive you. O children of Adam! If you were to come to Me with sins filling the whole world and then you came to Me without associating partners with Me, I would certainly match your sins with forgiveness." [At-Tirmidhi]

An-Nawwās ibn Sim‘ān (may Allah be pleased with him) reported that the Prophet (ﷺ) said: "Righteousness is good character, and sin is what wavers in your heart, and you dislike that people know about it." Wābisah ibn Ma‘bad (may Allah be pleased with him) reported: I went to the Messenger of Allah (ﷺ) and he said: "You have come to inquire about righteousness and sin." I said: Yes. He said: "Ask your heart. Righteousness is that which the soul feels at ease with and the heart feels tranquil about. And sin is that which wavers in your soul and causes uneasiness in your chest, even if people give you legal opinions and give you more opinions (in its favor)."

Grade: Authentic · Attribution: The first Hadīth: Narrated by Muslim, and the second Hadīth: Narrated by Ahmad and Ad-Dārimi