Is it permissible to kill an elderly person, a blind person, or a monk during conflict?

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It is forbidden to kill an elderly person (zaman), a blind person (a'ma), or a monk (rahib) during conflict. The evidence for the ruling concerning the elderly and the blind is that they are not considered people of combat, placing them in a similar category to women. Regarding the monk, the support comes from the narration of Abu Bakr As-Siddiq (may Allah be pleased with him), who said: "You will pass by people in their hermitages who have confined themselves therein; leave them until Allah causes them to die in their misguidance." Furthermore, since they do not fight for religious reasons, they resemble those incapable of fighting.