أَسْتَغْفِرُ اللهَ
“I seek Allah’s forgiveness.” (a Hundred Times)
*The Messenger of Allah (peace and blessings of Allah be upon him) said, “Verily my heart becomes preoccupied, and verily I seek Allah’s forgiveness a hundred times a day.” Note: Being 'preoccupied' means to be in a state of 'forgetfulness'. The Prophet (peace and blessings of Allah be upon him) always used to increase in his remembrance of his Lord, in attaining a nearness to Allah and having consciousness of Allah to the extent that if this intensity lessened in anyway, he would regard it as a sin and would then race to seek forgiveness from Allah.
Sources:
Muslim No# 2702; Abu Dawud No# 1515