Abū Dāwūd invoked this ḥadīth as proof for the point we have just outlined. He placed it under the heading, “Chapter: The Purification of the Ground When It Has Dried,” and then cited the report in full.

Ibn al-Qayyim states in Ighāthat al-Lahfān:

“Aḥmad gave an explicit ruling regarding the laundry line: if a soiled garment is hung on it and the sun dries it, a clean garment may afterwards be hung on the same line; he said, ‘There is no harm in that.’ This is identical to Abū Ḥanīfah’s view that impure ground is purified by wind and sunlight. It is likewise an acknowledged position among Aḥmad’s followers, to the extent that one may even perform tayammum with such ground. The report of Ibn ʿUmar is virtually a textual proof for this.”

I (the author) add: Ibn al-Qayyim then remarked, “This can only be coherently maintained by one who holds that the earth itself is purified by wind and sun.”

Shaykh ʿAlī al-Qārī, after quoting the ḥadīth in his work al-Mawḍūʿāt, wrote:

“Were desiccation not deemed to purify it, some trace of impurity would certainly remain, even though they unquestionably stand on those very spots for prayer, given the small size of the mosque and the large number of worshippers. This, then, amounts to a consensus that resolves the dispute.”

A fuller discussion of the issue has already appeared under the topic of removing impurities.

Second: Sheep enclosures. The Messenger of Allah ﷺ was asked about praying in sheep pens, and he replied, “Pray in them, for they are a blessing.” The chain of transmission is sound, and the report comes from al-Barāʾ b. ʿĀzib (may Allah be pleased with him).