Sahih al-Bukhari 6007
Narrated Abu Huraira:
Allah's Messenger (ﷺ) said, "The one who looks after and works for a widow and for a poor person is like a 
warrior fighting for Allah's Cause." (The narrator Al-Qa'nabi is not sure whether he also said "Like the 
one who prays all the night without slackness and fasts continuously and never breaks his fast.")
حَدَّثَنَا عَبْدُ اللَّهِ بْنُ مَسْلَمَةَ، حَدَّثَنَا مَالِكٌ، عَنْ ثَوْرِ بْنِ زَيْدٍ، عَنْ أَبِي الْغَيْثِ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏
"‏ السَّاعِي عَلَى الأَرْمَلَةِ وَالْمِسْكِينِ كَالْمُجَاهِدِ فِي سَبِيلِ اللَّهِ ـ وَأَحْسِبُهُ قَالَ، يَشُكُّ الْقَعْنَبِيُّ ـ كَالْقَائِمِ لاَ يَفْتُرُ، وَكَالصَّائِمِ لاَ يُفْطِرُ ‏"‏‏.‏