Riyad as-Salihin 1342
Jabir (May Allah be pleased with him) reported:
We accompanied the Prophet (ﷺ) in an expedition when he (ﷺ) said, "Some people have remained behind us in Al-Madinah, and we never cross a valley but they are with us. They share the reward with us because they have been held back by valid excuse." In another narration the wordings are: "...by any genuine excuse." In another narration the wordings are: "They are your partners in reward." [Al- Bukhari] .
وعن جابر رضي الله عنه قال‏:‏ كنا مع النبي صلى الله عليه وسلم في غزاة فقال‏:‏ ‏
"‏إن بالمدينة لرجالا ما سرتم مسيرًا، ولا قطعتم واديًا إلا كانوا معكم حبسهم المرض‏"‏