حَدَّثَنَا أَبُو كَامِلٍ، فُضَيْلُ بْنُ حُسَيْنٍ حَدَّثَنَا يَزِيدُ، - يَعْنِي ابْنَ زُرَيْعٍ - حَدَّثَنَا التَّيْمِيُّ، عَنْ أَبِي عُثْمَانَ، عَنْ أَبِي مُوسَى، أَنَّهُمْ كَانُوا مَعَ رَسُولِ اللَّهِ صلى الله عليه وسلم وَهُمْ يَصْعَدُونَ فِي ثَنِيَّةٍ - قَالَ - فَجَعَلَ رَجُلٌ كُلَّمَا عَلاَ ثَنِيَّةً نَادَى لاَ إِلَهَ إِلاَ اللَّهُ وَاللَّهُ أَكْبَرُ - قَالَ - فَقَالَ نَبِيُّ اللَّهِ صلى الله عليه وسلم ‏"‏ إِنَّكُمْ لاَ تُنَادُونَ أَصَمَّ وَلاَ غَائِبًا ‏"‏ ‏.‏ قَالَ فَقَالَ ‏"‏ يَا أَبَا مُوسَى - أَوْ يَا عَبْدَ اللَّهِ بْنَ قَيْسٍ - أَلاَ أَدُلُّكَ عَلَى كَلِمَةٍ مِنْ كَنْزِ الْجَنَّةِ ‏"‏ ‏.‏ قُلْتُ مَا هِيَ يَا رَسُولَ اللَّهِ قَالَ ‏"‏ لاَ حَوْلَ وَلاَ قُوَّةَ إِلاَّ بِاللَّهِ ‏"‏ ‏.‏

Abu Musa reported that he (and his other companions) were climbing upon the hillock along with Allah's Messenger (PBUH) and when any person climbed up, he pronounced (loudly): " There is no god but Allah, Allah is the Greatest." Thereupon Allah's Apostle (PBUH) said: Verily, you are not supplicating One Who is deaf or absent. He said: Abu Musa or Abdullah b Qais, should I not direct you to the words (which form) the treasure of Paradise? I said: Allah's Messenger, what are these? He said:" There is no might and no power but that of Allah." Translation Not Available

Book Ref: Sahih Muslim Book 48 Hadith 6528
Web Ref:  Sahih Muslim Book 35 Hadith 2704 c