Sahih al-Bukhari 4085
Narrated `Uqba:
One day the Prophet (ﷺ) went out and offered the (funeral) prayer for the people (i.e. martyrs) of Uhud as 
he used to offer a funeral prayer for any dead person, and then (after returning) he ascended the pulpit 
and said, "I am your predecessor before you, and I am a witness upon you, and I am looking at my 
Tank just now, and I have been given the keys of the treasures of the world (or the keys of the world). 
By Allah, I am not afraid that you will worship others besides Allah after me, but I am afraid that you 
will compete with each other for (the pleasures of) this world."
حَدَّثَنِي عَمْرُو بْنُ خَالِدٍ، حَدَّثَنَا اللَّيْثُ، عَنْ يَزِيدَ بْنِ أَبِي حَبِيبٍ، عَنْ أَبِي الْخَيْرِ، عَنْ عُقْبَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم خَرَجَ يَوْمًا فَصَلَّى عَلَى أَهْلِ أُحُدٍ صَلاَتَهُ عَلَى الْمَيِّتِ، ثُمَّ انْصَرَفَ إِلَى الْمِنْبَرِ فَقَالَ ‏
"‏ إِنِّي فَرَطٌ لَكُمْ، وَأَنَا شَهِيدٌ عَلَيْكُمْ، وَإِنِّي لأَنْظُرُ إِلَى حَوْضِي الآنَ، وَإِنِّي أُعْطِيتُ مَفَاتِيحَ خَزَائِنِ الأَرْضِ ـ أَوْ مَفَاتِيحَ الأَرْضِ ـ وَإِنِّي وَاللَّهِ مَا أَخَافُ عَلَيْكُمْ أَنْ تُشْرِكُوا بَعْدِي، وَلَكِنِّي أَخَافُ عَلَيْكُمْ أَنْ تَنَافَسُوا فِيهَا ‏"‏‏.‏