Abu Hurairah Radiyallahu anhu
narrates that Rasulullah Sallallahu 'alaihi wasallam said: Whenever a slave (of Allah) says La ilaha illallah sincerely, the doors of the skies are opened (for it to ascend) until it reaches the 'Arsh (Throne of Allah, and is readily accepted) provided he abstains from major sins. (Tirmidhi)
