"Glory be to Allāh! Has Allāh sent down any disease on earth without also providing a cure for it?" It was narrated by Imām Aḥmad (5/371): Isḥāq ibn Yūsuf narrated to us, Sufyān narrated from Manṣūr from Hilāl ibn Yasāf from Dhakwān from a man from the Anṣār who said: "The Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam) visited a man who had a wound, and the Messenger of Allāh (ṣallá Allāhu ʿalayhi wa-sallam) said: Call for him a doctor from the tribe of so-and-so. So they called him, and he came and said: O Messenger of Allāh, does medicine benefit anything? He said..." and he mentioned it. I say: This isnād is authentic; all its narrators are reliable and known from the narrators of Muslim, except for the Anṣārī man, who is a Companion as it appears, and the unknown status of a Companion does not harm, especially since the essence of the ḥadīth is well-known from the Prophet (ṣallá Allāhu ʿalayhi wa-sallam) and was narrated by a group of Companions, including Anas ibn Mālik, Abū Saʿīd al-Khudrī, Abū Hurayrah, Jābir, Usāmah ibn Sharīk, ʿAbd Allāh ibn Masʿūd, and Ṣafwān ibn ʿAssāl. I have produced their ḥadīths and discussed their isnāds, and most of them are authentic in "Takhrīj Aḥādīth al-Ḥalāl wa-al-Ḥarām" number (290). I have only mentioned this here for the benefit that is unique to it, clarifying the reason for the ḥadīth's occurrence. All praise is due to Allāh for His guidance.

"Indeed, Allāh did not send down a disease except that He also sent down a cure for it, except for old age. So, you should use cow's milk, for it feeds on every tree." It was narrated by al-Ṭayālisī (368): al-Masʿūdī narrated to us from Qays ibn Muslim from Ṭāriq ibn Shihāb from ʿAbd Allāh from the Prophet (ṣallá Allāhu ʿalayhi wa-sallam). And from this chain, it was also narrated by al-Ḥākim (1/197). Its narrators are reliable, except that al-Masʿūdī had become confused before his death, and his name is ʿAbd al-Raḥmān ibn ʿAbd Allāh ibn ʿUtbah ibn Masʿūd al-Kūfī, but he was followed up, as it was also narrated by al-Ṭabarānī in "al-Muʿjam al-Kabīr" (3/49/1) through the route of Zufar ibn al-Hudhayl from Abū Ḥanīfah from Qays ibn Muslim with it. And this is a follow-up that is acceptable, and Yazīd ibn Abī Khālid contradicted them, saying: from Qays ibn Muslim from Ṭāriq ibn Shihāb that the Prophet (ṣallá Allāhu ʿalayhi wa-sallam) said: and he mentioned it. He did not mention ʿAbd Allāh, who is Ibn Masʿūd