What did the Prophet Muhammad (saw) say about performing acts of devotion like praying and fasting in Ramadan with sincere faith and hoping for a reward from Allah?
 Narrated Abu Huraira:                     The Prophet said, "Whoever established prayers on the night of Qadr out of sincere faith and hoping for a reward from Allah, then all his previous sins will be forgiven; and whoever fasts in the month of Ramadan out of sincere faith, and hoping for a reward from Allah, then all his previous sins will be forgiven."