The answer is that this hadith (1) is authentic. Both al-Bukhārī and Muslim recorded it in their Sahīh collections (2), in the hadith of al-Barā ibn Āzib: “When Alī, Jafar (3), and Zayd disputed over Hamza’s daughter, he placed her in the care of her maternal aunt, who was married to Jafar. He said to Alī, ‘You are from me, and I am from you’; to Jafar, ‘You resemble me in appearance and character’; and to Zayd, ‘You are our brother and our freedman.’” (4)

However, the Prophet—may Allah bless him and grant him peace—used this same expression concerning a number of his Companions. As recorded in the two Sahīh collections, Abū Mūsā al-Asharī reported that the Prophet—may Allah bless him and grant him peace—said:

“When the Asharīs’ provisions run out during a military campaign (5), or their families’ provisions in Medina (7) run short (6), they gather whatever they have in a single cloth and then divide it equally among themselves. They are from me, and I am from them.” (8)

Likewise, he said concerning Julaybīb (9): “He is from me, and I am from him.” Muslim narrated in his Sahīh (10) from Abū Barza, who said: “We were with the Prophet—may Allah bless him and grant him peace—on one of his military campaigns (11). Allah granted him spoils, and he asked his Companions, ‘Is anyone missing?’