رَبَّنَا وَسِعْتَ كُلَّ شَيْءٍ رَحْمَةً وَعِلْمًا. فَاغْفِرْ لِلَّذِينَ تَابُوا وَاتَّبَعُوا سَبِيلَكَ وَقِهِمْ عَذَابَ الْجَحِيمِ.
Our Lord, You have encompassed all things in mercy and knowledge, so forgive those who have repented and followed Your way and protect them from the punishment of Hellfire.
Rabbana wasita kulla shay’irrahmatawwa ilma, faghfir lilladhina tabu wattabau sabilaka wa qihim adhabaljahim.
One of the tremendous benefits of Eman is that Allah’s angels ask forgiveness for the Believers. The angels, of course, are a creation that can only do as Allah commands, and so they are sinless. Furthermore, they appeal to Allah by means of His all-encompassing mercy and knowledge. And so, the sheer breadth of His mercy is enough to wipe out the sins of those who repent with sincerity, and He is all knowing of everything His servants say and do. -Tafseer As-Sa’di, Ibn Katheer and others.