Abu Rafi narrated that :
Allah's Messenger said to Al-Abbas: O uncle! Shall I not give to you, shall I not present to you, shall I not benefit you? He said: Of course, O Messenger of Allah! He said: O uncle! Pray four Rak'ah, reciting in each Rak'ah Fatihatil-Kitab and a Surah. When you are finished your recitation then say: Allahu Akbar, wal-hamdulilah, wa Subhan-Allah, [Wa La Ilaha illallah] 'Allah is Greatest, and all praise is due to Allah, and Glorious is Allah, [and there is none worthy of worship except Allah].' fifteen times before you bow. Then bow and say it ten times, then raise your head and say it ten times. Then prostrate [the second time] and say it ten times. Then raise your head and say it ten times before standing. That is seventy-five in every Rak'ah, which is three-hundred in four Rak'ah. If your sins were like a heap of sand then Allah would forgive you. He said: O Messenger if Allah! Who is able to say that every day? He said: If you can not say it every day then say it every Friday, and if you are not able to say it every Friday then say it every month. And he did not stop saying that until he said: Then say it every year.