رَبَّنَا ظَلَمْنَا أَنْفُسَنَا وَإِنْ لَمْ تَغْفِرْ لَنَا وَتَرْحَمْنَا لَنَكُونَنَّ مِنَ الْخَاسِرِينَ
Rabbana zalamna anfusana wa in lam taghfir lana wa tarhamna lanakuanna minal-khasirin
我们的主啊!我们已亏害了自己。如果你不饶恕我们,不慈悯我们,我们必定是亏折者。
Recite when seeking forgiveness for sins and mistakes
This was the first dua of repentance taught to humanity. Adam and Hawwa (Eve) said this after their sin, and Allah accepted their repentance.