سورة At-Taubah ( The Repentance ) - الآية 91

There is no blame on those who are weak or ill or who find no resources to spend [in holy fighting (Jihad)], if they are sincere and true (in duty) to Allah and His Messenger. No ground (of complaint) can there be against the Muhsinun (good-doers - see the footnote of V. 9:120). And Allah is Oft-Forgiving, Most Merciful.