كتاب الإمارة
33  
The Book on Government
(39)
Chapter: The sanctity of the wives of the Mujahidin, and the sin of the one who betrays them with regard to them
(39)
باب حُرْمَةِ نِسَاءِ الْمُجَاهِدِينَ وَإِثْمِ مَنْ خَانَهُمْ فِيهِنَّ ‏‏
Sahih Muslim 1897 c

A version of the tradition narrated on the authority of 'Alqama b. Murthad has a differently worded end:

It will be said to the Mujahid: Take from his noble deeds whatever you like. Then the Messenger of Allah (ﷺ) turned to us and asked: What do you think (will he leave anything)? - (i. e. he will take away everything).
وَحَدَّثَنَاهُ سَعِيدُ بْنُ مَنْصُورٍ، حَدَّثَنَا سُفْيَانُ، عَنْ قَعْنَبٍ، عَنْ عَلْقَمَةَ بْنِ مَرْثَدٍ، بِهَذَا الإِسْنَادِ ‏"‏ فَقَالَ فَخُذْ مِنْ حَسَنَاتِهِ مَا شِئْتَ ‏"‏ ‏.‏ فَالْتَفَتَ إِلَيْنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فَقَالَ ‏"‏ فَمَا ظَنُّكُمْ ‏"‏ ‏.‏
Reference : Sahih Muslim 1897c
In-book reference : Book 33, Hadith 205
USC-MSA web (English) reference : Book 20, Hadith 4675
  (deprecated numbering scheme)