Is it permissible to kill an old, infirm man (*shaykh fānin*) during conflict?
General Chapter
Al-Mughni
Book of Jihad
Primary text
The killing of an old, infirm man is prohibited. This opinion is held by Malik, the Ashab al-Ra'y, and is narrated from Abu Bakr al-Siddiq. Evidence includes the Prophet's saying, "Do not kill an old, decaying man (*shaykh fānin*), nor a child, nor a woman," narrated by Abu Dawud. Umar also commanded Salama ibn Qays, saying, "Do not kill a woman, nor a child, nor an old, decaying man." The rationale is that he is not fit for combat, thus he is not killed, analogous to a woman.
Supporting text
There is a dissenting view held by Al-Shafi'i, in one of his two opinions, and Ibn al-Mundhir, who permit the killing of old men based on the Prophet's saying, "Kill the old men of the polytheists, and spare their youth" (narrated by Abu Dawud and Al-Tirmidhi). They also cite the general command in the Quran: "So kill the polytheists" (Quran 9:5), arguing it encompasses the elderly. Ibn al-Mundhir states he knows no evidence to exempt the elderly from this general command, viewing them as disbelievers with no benefit in their continued life.