Language:
كتاب فرض الخمس
57  
One-fifth of Booty to the Cause of Allah (Khumus)
(14)
Chapter: If the Imam sends some messenger to carry out a certain duty, or orders one to stay at home, will he be given a share from the booty?
(14)
باب إِذَا بَعَثَ الإِمَامُ رَسُولاً فِي حَاجَةٍ أَوْ أَمَرَهُ بِالْمُقَامِ هَلْ يُسْهَمُ لَهُ
Sahih al-Bukhari 3130

Narrated Ibn `Umar:

`Uthman did not join the Badr battle because he was married to one of the daughters of Allah's Apostle and she was ill. So, the Prophet (ﷺ) said to him. "You will get a reward and a share (from the war booty) similar to the reward and the share of one who has taken part in the Badr battle."

حَدَّثَنَا مُوسَى، حَدَّثَنَا أَبُو عَوَانَةَ، حَدَّثَنَا عُثْمَانُ بْنُ مَوْهَبٍ، عَنِ ابْنِ عُمَرَ ـ رضى الله عنهما ـ قَالَ إِنَّمَا تَغَيَّبَ عُثْمَانُ عَنْ بَدْرٍ، فَإِنَّهُ كَانَتْ تَحْتَهُ بِنْتُ رَسُولِ اللَّهِ صلى الله عليه وسلم وَكَانَتْ مَرِيضَةً‏.‏ فَقَالَ لَهُ النَّبِيُّ صلى الله عليه وسلم ‏ "‏ إِنَّ لَكَ أَجْرَ رَجُلٍ مِمَّنْ شَهِدَ بَدْرًا وَسَهْمَهُ ‏"‏‏.‏
Reference : Sahih al-Bukhari 3130
In-book reference : Book 57, Hadith 39
USC-MSA web (English) reference : Vol. 4, Book 53, Hadith 359
  (deprecated numbering scheme)