Dua 1
Abdullah bin Umar (RA) narrated that in a single gathering, before getting up, Allah's Messenger would say a hundred times:
رَبِّ اغْفِرْ لِيْ وَتُبْ عَلَيَّ اِنَّكَ اَنْتَ التَّوَّابُ الْغَفُوْرُ
My Lord, forgive me and accept my repentance. Indeed, You are the Accepter of repentance, the Most Forgiving.
Sahih, Sunan at-Tirmidhi, no. (3434), the wording is his, Sunan Abi Dawud, no. (1516), Sunan Ibn Majah, no. (3814), Musnad Ahmad (2/21), Sahih Ibn Hibban, no. (927), and al-Albani graded it Sahih in “as-Sahihah” no. (556).