Narrated Humran Radi Allahu Anhu (the slave of ‘Uthman) After performing the ablution Uthman Radi Allahu Anhu said, “I am going to tell you a Hadith which I would not have told you, had I not been compelled by a certain Holy Verse I heard the Prophet Sallallahu Alaihi Wasallam saying, ‘If a man performs ablution perfectly and then offers the compulsory congregational prayer, Allah will forgive his sins committed between that (prayer) and the (next) prayer till he offers it.
Sahih Bukhari, Volume 1, Book 4, Number 161

(the sub narrator urwa Radi Allahu Anhu said: This verse is: “Verily, those who conceal the clear signs and the guidance which we have sent down…
Al Quran: 2:159).