Rabbigh’fir līwa tub `alayyinnaka antat-Tawwābu ‘l-Ghafūr.
Ibn Umar (ra) said: Allah's Messenger (ﷺ) used to repeat in a single sitting: My Lord, forgive me, and accept my repentance, You are the Ever-Relenting, the All-Forgiving.
Reference:
Sahih Ibn Majah 2/321. See also Al-Albani, Sahih At-Tirmidhi 3/153.
Hisnul Muslim 195
Sahih Ibn Majah 2/321. See also Al-Albani, Sahih At-Tirmidhi 3/153.
Hisnul Muslim 195