It is weak; even when the report is transmitted as “traced back to the Prophet,” its isnād contains a narrator who has been discarded, as noted in Nayl al-Awṭār. I have fully documented the narration in al-Ṣaḥīḥa wa-l-Ḍaʿīfa, no. 4386. Ibn Ḥazm (d. 456 AH) delivered an incisive refutation of this very distinction at the close of the first volume of al-Muḥallā—consult it if you wish. The same rebuttal is found in the Qur’ānic commentaries of al-Qurṭubī and Ibn al-ʿArabī; see, for example, al-Jāmiʿ li-Aḥkām al-Qur’ān, 8 / 263.

What is truly remarkable is that the author here declares every kind of blood to be impure, without exempting the blood of animals whose flesh is lawful to eat, yet later he differentiates between the inherently impure urine of a human being and the urine of such edible animals, which he judges to be pure, invoking the principle of original purity and the presumption of non-liability. Why, then, did he not apply the very same principle in the matter of blood, since the evidence in both cases is identical?