What is the reality and virtue of seeking forgiveness with the intention of hastening the answer to a prayer, and what is its formula?

Seeking forgiveness (Istighfar) is one of the great forms of remembrance (dhikr), and there is an encouragement to increase in it in the Holy Quran, as conveyed by Noah and Hud (peace be upon them), and by Allah Almighty to this nation.

Seeking forgiveness is one of the reasons for the acceptance of supplications (du'a), as it is among the righteous deeds through which one may seek a means of nearness to Allah (tawassul) to achieve what is desired, as mentioned by Ibn Al-Qayyim and Al-Baydawi.

Seeking forgiveness can be done by any formula that denotes it, but it is best to limit oneself to the formulas authentically reported in the Quran and Sunnah.