Ma'arif al-Qur'an
Mufti Muhammad Shafiوَيُطْعِمُوْنَ الطَّعَامَ عَلٰي حُبِّهٖ مِسْكِيْنًا وَّيَـتِـيْمًا وَّاَسِيْرًا (and they give food, despite their love for it, to the needy, and the orphan, and the captive... 76:8). The other reason why the inmates of Paradise will receive these favours is given in this verse, that is, their feeding the needy, the orphans and the captives.عَلٰي حُبِّهٖ (despite their love for it). This would mean that they give food to the needy while they themselves love it and desire it_ not that they eat to their fill and give the left-over food to the needy and poor. That feeding the poor and orphans is a form of worship and attracts reward is obvious. The word 'captive' refers to all prisoners, Muslim criminals, as well as infidels who are kept in prisons according to the principles of Shari` ah. It is the responsibility of the Islamic government to feed them. Anyone who feeds them is actually assisting the government and the public treasury. Therefore, feeding the prisoners, even Non-Muslims, is an act of reward.
In the early days of Islam, especially, feeding the prisoners and taking care of them or protecting them was a responsibility that was shared by the general body of Muslims, as it happened with the prisoners of the Battle of Badr.