Aishah reported that the Messenger of Allah ﷺ came in to her looking delighted, the lines of his face beaming with joy. He said, "Did you not see that Mujazziz just looked at Zayd bin Haritha and Usama bin Zayd and said, 'These feet belong to one another.'"
إن رسول الله ﷺ دخل علي مسرورا تبرق أسارير وجهه، فقال: ألم تري أن مجززا نظر آنفا إلى زيد بن حارثة وأسامة بن زيد فقال: إن هذه الأقدام بعضها من بعض.
Bukhari narrated it in the Book of Legal Punishments (6770) and Muslim in the Book of Breastfeeding (1459), both from Qutayba bin Saeed, who said, "Layth narrated to us, from Ibn Shihab, from Urwa, from Ayesha," and he mentioned it.Mujazziz, with the jeem vocalized with fatha and the zay with kasra according to the well-known reading. It is also said that he was named Mujazziz because whenever he took a captive, he would cut off his forelock.Abu Dawud said, "I heard Ahmad bin Salih say, 'Usama was black, intensely black, like tar, while Zayd (meaning Ibn Haritha) was white like cotton.'" Sunan (2268).Zayd bin Haritha bin Sharahil Kalbi had been captured as a slave in the pre-Islamic era. Hakeem bin Hizam bought him in the market of Hubasha in Makkah for his paternal aunt Khadijah bint Khuwaylid, who then gave him to the Prophet ﷺ as a gift. The Prophet adopted him before the start of his prophethood, when Zayd was eight years old, and the Messenger of Allah ﷺ was twenty years older than him. He used to be called Zayd bin Muhammad until the revelation of Allah's saying, "Call them by their fathers" [Ahzab 33:5], after which he was called Zayd bin Haritha.Usama was the son of Zayd, and his mother was Umm Ayman, whose name was Baraka, an Abyssinian woman who was black, which is why Usama was black.The hypocrites used to cast doubt on the lineage of Usama bin Zayd, since Usama was black in complexion while his father Zayd was white like cotton. So when the tracker of footprints said, "These feet, part of them come from the other," the Prophet ﷺ was pleased.The majority of scholars relied on this to establish the principle of resorting to the statement of an expert tracker of footprints when there is doubt about a child's parentage, since the Prophet ﷺ would not have been pleased by something false. Abu Hanifa, however, did not adopt this position, holding instead to the Prophet's ﷺ dismissal of resemblance as evidence in the hadith of lian and in the hadith stating that the child belongs to the marriage bed. But there is a difference between the two cases, for in lian and in the ruling that the child belongs to the marriage bed, there existed a stronger counter-evidence than the hadith of the tracker, whereas in this hadith there is no counter-evidence at all.