{Whoever among you is sick} (meaning with sores on his head), {or has an ailment of the head} (meaning lice). Then, one must observe: if the harm reaching him is from the hair itself, such as it growing into his eyes, or his eyebrows becoming long and covering his eyes, then he may pluck what is in the eye and cut what has extended over his eyes, and there is no fidya (expiatory ransom) upon him; because the hair has harmed him, so he may repel its harm without fidya, just like game/hunting prey if it attacks him. If the harm is from something other than the hair, but he is unable to remove the harm except by removing the hair, such as lice or sores on his head, or a headache, or severe heat upon him due to the thickness of his hair, then the fidya is upon him; because he cut the hair to remove a harm other than it, so it is similar to eating game for dire hunger. If it is said: "Lice are from the harm of the hair, and heat is caused by the thickness of the hair," we reply: Lice are not from the hair; rather, one is unable to reside on the head except by means of it, so it is a location for it, not a cause of it. Likewise, heat is from the weather, evidenced by the fact that hair exists in cold weather, yet one is not harmed by it. And Allah knows best.

584 - Issue: He said: (And he shall not cut a nail unless it breaks.)

The scholars are in consensus that the muhrim is prohibited from clipping his nails, except out of necessity; because cutting nails is the removal of a part that one derives comfort from, so it is prohibited, just like removing hair. If it breaks, he may remove it without a fidya being required of him. Ibn al-Mundhir said: "Every scholar from whom we possess knowledge is in consensus that the muhrim may remove his nail himself if it breaks." And because what has broken harms him and causes him pain, so it is similar to hair growing into his eye or game attacking him. If he cuts more than what broke, then the fidya is upon him for that excess, just as if he cut more hair than he needed. And if he needs to treat a sore, and he cannot do so except by cutting his nails, then the fidya is upon him for that. Ibn...