Al-Mu'minun 23:118
وَقُل رَّبِّ ٱغْفِرْ وَٱرْحَمْ وَأَنتَ خَيْرُ ٱلرَّٰحِمِينَ
Waqul rabbi ighfir warhamwaanta khayru arrahimeen
"And, [O Muḥammad], say, "My Lord, forgive and have mercy, and You are the best of the merciful.""
Al-Mu'minun 23:118, translation by Sahih International
A short reflection
My Lord, forgive and have mercy, for You are the best of the merciful. The closing dua of Surah al-Muminun.