The Messenger of Allah ﷺ commanded us to carefully examine the eye and the ear.
أمرنا رسول الله ﷺ أن نستشرف العين والأذن.
This was narrated by Tirmidhi (1503), Nasai (4376), Ibn Majah (3143), and Imam Ahmad (732, 734, 826, 1021) through various routes from Salama bin Kuhayl, from Hujayya bin Adi, from Ali, who related it. Tirmidhi and Ahmad added, except in the first instance, that Ali was asked about the cow, and he said, "Seven people may share it." He was asked, "What about a horned one?" He said, "That does no harm." He was asked, "What about a lame one?" He said, "If it can reach the place of sacrifice." Tirmidhi said, "Hasan sahih," and Ibn Khuzayma (2914, 2915) and Ibn Hibban (5920) also graded it sahih from this route.Hakim narrated it (4/224–225) through the route of Abu Ishaq, Thawri, and Shuba, separately, all three from Salama bin Kuhayl with the same wording. He then said, "All these chains are sahih, though the two of them (Bukhari and Muslim) did not use Hujayya bin Adi as evidence, even though he was among the senior companions of the Commander of the Faithful, Ali." End of quote.I say, this Hujayya is disputed, though his hadith is hasan. Moreover, he is not alone in relating it, for Hubayra bin Yarim corroborated him, and his hadith is found among the additions of Abdullah bin Ahmad (1106). Hubayra bin Yarim is similar in standing to Hujayya. Shurayh bin Numan also corroborated him, and his hadith was narrated by Abu Dawud (2804), Tirmidhi (1498), Nasai (4372), Ibn Majah (3142), and Ahmad (851), and Hakim (4/224) graded its chain sahih. Shurayh bin Numan is truthful.In summary, the hadith is hasan, although scholars differ over whether it is a mawquf or marfu narration, and the marfu version represents an addition.As for his statement, "We closely examine the eye and the ear," it means that we look carefully to ensure they are free from defects such as blindness or amputation. Istishraf refers to placing one's hand over one's eyebrow, as one does when shading the eyes from the sun, in order to see something clearly.