The second [narration]: It is not mandatory; because hardship is attached to that, so it is pardoned, like the area of cleaning oneself after relieving nature (istinja) and the bottom of shoes.

Section: Muhammad ibn Yahya said: I asked Abu Abd Allah regarding stone graves belonging to the Romans (Rum) into which rain enters, and they drink from it and perform wudu from it. He said: If they were to be washed, how would they be washed! Rain only arrives unless it has already washed them once or twice. The preferred view is to judge them as pure; because water has reached them countless times, and rainwater has flowed over their walls which purifies some of it, and because it is difficult to wash them, so they are analogous to the earth which is purified by the arrival of rain upon it.

6 - Issue: He said: (And if that which has no flowing blood dies in a small amount of water, such as flies, scorpions, beetles, and the like, it does not make it impure.)

"Nafs" here means: blood. Meaning: that which has no flowing blood. The Arabs call blood "nafs". The poet said (1):

I was informed that the sons of Suhaym have introduced Into their houses the heart's blood of the nafs (soul/person) of al-Mundhir.

Meaning: his blood (2). From this, a woman is called "nufasa'" (postpartum) due to the flowing of her blood during childbirth, and the Arabs say: "Nufisat" (3) the woman, when she menstruates, and she is "nufisat" from nifas (postpartum bleeding).