Fatimah the Great narrated:
When Allah's Messenger entered the Masjid he said Salat and Salam upon Muhammad and then said: (Rabbighfirli dhunubi, waftahli abwaba rahmatik) 'O pardon my sins, and open the gates of Your mercy for me.' And when he exited he said Salat and Salam upon Muhammad, and then said: (Rabbighfirli dunubi, waftahli abwaba rakmatik) 'O Lord pardon my sins, and open the gates of Your blessings for me.'