(Imam Bukhari narrates that) Isma'il narrated to us, he said: Imam Malik narrated to me, from Ibn Shihab, from Humaid bin Abdur Rahman, from Hazrat Abu Hurairah (may Allāh be pleased with him), he says that the Messenger of Allāh ﷺ said:

Whoever stood (in prayer) in Ramadan with faith and seeking reward, his previous sins will be forgiven.