وَعَنْ أَبِي سَعِيدٍ الْخُدْرِيِّ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: " قَالَ مُوسَى عَلَيْهِ السَّلَامُ: يَا رَبِّ عَلِّمْنِي شَيْئًا أَذْكُرُكَ بِهِ وَأَدْعُوكَ بِهِ فَقَالَ: يَا مُوسَى قُلْ: لَا إِلَهَ إِلَّا اللَّهُ فَقَالَ: يَا رَبِّ كلُّ عبادكَ يقولُ هَذَا إِنَّما أيد شَيْئًا تَخُصُّنِي بِهِ قَالَ: يَا مُوسَى لَوْ أَنَّ السَّمَاوَاتِ السَّبْعَ وَعَامِرَهُنَّ غَيْرِي وَالْأَرَضِينَ السَّبْعَ وُضِعْنَ فِي كِفَّةٍ وَلَا إِلَهَ إِلَّا اللَّهُ فِي كِفَّةٍ لَمَالَتْ بِهِنَّ لَا إِلَهَ إِلَّا اللَّهُ ". رَوَاهُ فِي شرح السّنة

Abu Sa'id al-Khudri reported God’s messenger as saying that Moses asked his Lord to teach him something with which to make mention of Him or to supplicate Him, and was told to say, “There is no god but God.” He replied to his Lord that all His servants said this, but he wanted something particularly for himself, and He said, “Moses, were the seven heavens and their inhabitants apart from me and the seven earths put in one side of a balance and ‘There is no god but God’ in the other, ‘There is no god but God’ would outweigh them.” It is transmitted in Shar as-sunna.