What is the authenticity of the Hadith: "Umar ibn al-Khattab entered upon the Messenger of Allah, may Allah's peace and blessings be upon him, while he was weeping... so he said, 'Indeed, Allah forgives your sin, even if it were like the seven heavens, the seven earths, and the firm mountains'?"

This hadith has not been found in the reliable Sunnah books. What is mentioned in it regarding the vastness of Allah's mercy and forgiveness is established by other texts from the Qur'an and Sunnah, such as the Almighty's saying: "Say, 'O My servants who have transgressed against themselves [by sinning], do not despair of the mercy of Allah. Indeed, Allah forgives all sins. Indeed, it is He who is the Forgiving, the Merciful.'" and the hadith narrated by al-Tirmidhi: "O son of Adam, as long as you invoke Me and hope in Me, I will forgive you for what you have done, and I do not care." A Muslim should maintain a balance between fear and hope.