Anas said that:
The Prophet (ﷺ) entered the Masjid and there was a man who had performed Salat and was supplicating. He was saying in his supplication: "O Allah, none has the right to be worshipped but Allah, You are the One Who gives blessings, Originator of the heavens and the earth, Possessor of glory and generosity (Allāhumma lā ilāha illā ant, al-Mannān, Badī`us-samāwāti wal-arḍ, Dhal-Jalāli wal Ikrām)." So the Prophet (ﷺ) said: "Do you know what he has supplicated Allah with? He has supplicated to Allah by His Greatest Name, the one which if He Is called upon by it, He responds, and when He is asked by it, He gives."
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ أَبِي الثَّلْجِ، - رَجُلٌ مِنْ أَهْلِ بَغْدَادَ أَبُو عَبْدِ اللَّهِ صَاحِبُ أَحْمَدَ بْنِ حَنْبَلٍ حَدَّثَنَا يُونُسُ بْنُ مُحَمَّدٍ، حَدَّثَنَا سَعِيدُ بْنُ زَرْبِيٍّ، عَنْ عَاصِمٍ الأَحْوَلِ، وَثَابِتٍ، عَنْ أَنَسٍ، قَالَ دَخَلَ النَّبِيُّ صلى الله عليه وسلم الْمَسْجِدَ وَرَجُلٌ قَدْ صَلَّى وَهُوَ يَدْعُو وَيَقُولُ فِي دُعَائِهِ اللَّهُمَّ لاَ إِلَهَ إِلاَّ أَنْتَ الْمَنَّانُ بَدِيعُ السَّمَوَاتِ وَالأَرْضِ ذَا الْجَلاَلِ وَالإِكْرَامِ . فَقَالَ النَّبِيُّ صلى الله عليه وسلم
" تَدْرُونَ بِمَ دَعَا اللَّهَ دَعَا اللَّهَ بِاسْمِهِ الأَعْظَمِ الَّذِي إِذَا دُعِيَ بِهِ أَجَابَ وَإِذَا سُئِلَ بِهِ أَعْطَى "
. قَالَ أَبُو عِيسَى هَذَا حَدِيثٌ غَرِيبٌ مِنْ حَدِيثِ ثَابِتٍ عَنْ أَنَسٍ . وَقَدْ رُوِيَ مِنْ غَيْرِ هَذَا الْوَجْهِ عَنْ أَنَسٍ .
