لَّيْسَ عَلَى الْأَعْمَى حَرَجٌ وَلَا عَلَى الْأَعْرَجِ حَرَجٌ وَلَا عَلَى الْمَرِيضِ حَرَجٌ وَمَن يُطِعِ اللَّهَ وَرَسُولَهُ يُدْخِلْهُ جَنَّاتٍ تَجْرِي مِن تَحْتِهَا الْأَنْهَارُ وَمَن يَتَوَلَّ يُعَذِّبْهُ عَذَابًا أَلِيمًا
There is no blame on the blind, nor is there any blame on the lame, nor is there blame on the sick [if they are unable to go out with the troops to face the enemies]; and whoever obeys Allah and His Apostle, He will admit him into gardens with streams running in them, and whoever refuses to comply, He will punish him with a painful punishment.
Agha Ali Puya Commentary
Commentary on Quran 48:17
[Pooya/Ali Commentary 48:17] The blind, the maimed and the infirm are exempted from active compliance with the call to jihad. Those who obey the Holy Prophet's call to jihad will get the spiritual rewards of the hereafter, and those who turn back, desert and abandon the Holy Prophet will be punished. See commentary of Bara-at: 25 to 27 to know about the deserters.