Sahih Muslim Book - 48, Hadith - 6840

حَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ ، حَدَّثَنَا إِسْمَاعِيلُ ، يَعْنِي ابْنَ عُلَيَّةَ ، عَنْ عَبْدِ الْعَزِيزِ ، وَهُوَ ابْنُ صُهَيْبٍ ، قَالَ: سَأَلَ قَتَادَةُ أَنَسًا أَيُّ دَعْوَةٍ كَانَ يَدْعُو بِهَا النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَكْثَرَ ، قَالَ: كَانَ أَكْثَرُ دَعْوَةٍ يَدْعُو بِهَا يَقُولُ : اللَّهُمَّ آتِنَا فِي الدُّنْيَا حَسَنَةً وَفِي الآخِرَةِ حَسَنَةً ، وَقِنَا عَذَابَ النَّارِ. قَالَ: وَكَانَ أَنَسٌ إِذَا أَرَادَ أَنْ يَدْعُوَ بِدَعْوَةٍ دَعَا بِهَا ، فَإِذَا أَرَادَ أَنْ يَدْعُوَ بِدُعَاءٍ دَعَا بِهَا فِيهِ.

It was narrated that 'Abdul-'Aziz bin Suhaib said: Qatadah asked Anas: Which supplication did the Prophet (s.a.w) say the most?' He said: The supplication that he said the most was: "Allahumma atina fid-dunya' hasanah wa fil-akhirati hasanah, wa qina 'adhaban-nar. (O Allah, give us good in this world and good in the Hereafter and save us from the torment of the Fire.)" When Anas wanted to say a supplication, he would say these words, and when he had a specific need he would include these words in his supplication.