Sahih al-Bukhari 1868
Narrated Anas:
The Prophet (ﷺ) came to Medina and ordered a mosque to be built and said, "O Bani Najjar! Suggest to 
me the price (of your land)." They said, "We do not want its price except from Allah" (i.e. they wished 
for a reward from Allah for giving up their land freely). So, the Prophet (ﷺ) ordered the graves of the 
pagans to be dug out and the land to be leveled, and the date-palm trees to be cut down. The cut datepalms 
were fixed in the direction of the Qibla of the mosque.
حَدَّثَنَا أَبُو مَعْمَرٍ، حَدَّثَنَا عَبْدُ الْوَارِثِ، عَنْ أَبِي التَّيَّاحِ، عَنْ أَنَسٍ ـ رضى الله عنه ـ قَدِمَ النَّبِيُّ صلى الله عليه وسلم الْمَدِينَةَ فَأَمَرَ بِبِنَاءِ الْمَسْجِدِ فَقَالَ ‏
"‏ يَا بَنِي النَّجَّارِ ثَامِنُونِي ‏"‏‏.‏ فَقَالُوا لاَ نَطْلُبُ ثَمَنَهُ إِلاَّ إِلَى اللَّهِ‏.‏ فَأَمَرَ بِقُبُورِ الْمُشْرِكِينَ، فَنُبِشَتْ، ثُمَّ بِالْخِرَبِ فَسُوِّيَتْ، وَبِالنَّخْلِ فَقُطِعَ، فَصَفُّوا النَّخْلَ قِبْلَةَ الْمَسْجِدِ‏.‏