Abu ‘Abdullāh Jābir ibn ‘Abdullāh al-Ansāri (may Allah be pleased with him) reported: We were with the Prophet (may Allah's peace and blessings be upon him) on an expedition, and he said: "In Madīnah, there are people who are with you whenever you cover a distance or cross a valley. They have been detained by illness.'' Another narration reads: ''They have shared the reward with you." Anas (may Allah be pleased with him) said: ''When we returned from the battle of Tabūk with the Prophet (may Allah's peace and blessings be upon him) he said: 'There are people whom we left behind in Madīnah who accompany us in spirit in every pass and valley we cross. They have been detained by a valid excuse.'''
شرح الحديث :
The Prophet (may Allah's peace and blessings be upon him) talks about some men who could not participate in Jihad because they were sick or had other valid excuses. He stresses that whenever the Muslim fighters travel a distance or cross a valley or a defile, those who are detained get reward for such actions as well.