Allah addressed His servant and Messenger Muhammad , saying:
[وَيَوْمَ نَبْعَثُ 
فِى كُلِّ أُمَّةٍ شَهِيدًا عَلَيْهِمْ مِّنْ أَنفُسِهِمْ وَجِئْنَا بِكَ شَهِيدًا 
عَلَى هَـؤُلآءِ]
(And on the Day when We resurrect a witness from each nation from among 
themselves, and We bring you (O Muhammad) as a witness against these.), meaning, 
your Ummah. The Ayah means: remember that Day and its terrors, and the great 
honor and high position that Allah has bestowed upon you. This Ayah is like the 
Ayah with which `Abdullah bin Mas`ud ended when he recited to the Messenger of 
Allah from the beginning of Surat An-Nisa'. When he reached the Ayah:
[فَكَيْفَ إِذَا 
جِئْنَا مِن كُلِّ أمَّةٍ بِشَهِيدٍ وَجِئْنَا بِكَ عَلَى هَـؤُلاءِ شَهِيداً 
]
(How (will it be) then, when We bring from each nation a witness and We bring 
you (O Muhammad) as a witness against these) [4:41] the Messenger of Allah said 
to him:
«حَسْبُك»
(Enough.) Ibn Mas`ud said: "I turned to him and saw his eyes streaming with 
tears.''