The Book of Funerals
21/22. Chapter:
The Command to seek Reward and be Patient at the time of Calamity
Sunan an-Nasai
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، قَالَ حَدَّثَنَا شُعْبَةُ، عَنْ ثَابِتٍ، قَالَ سَمِعْتُ أَنَسًا، يَقُولُ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " الصَّبْرُ عِنْدَ الصَّدْمَةِ الأُولَى " .
It was narrated that Thabit said: "I heard Anas say: 'The Messenger of Allah said: True patience is that which comes at the first blow."'
Reference : Sunan an-Nasa'i 1869In-book reference : Book 21, Hadith 52English translation : Vol. 3, Book 21, Hadith 1870