Muslim

Hadith Commentary: Benefits and Issues: Zayd radi Allahu anhu was a child when, during the era of ignorance (Jahiliyyah), people from the Banu Qayn tribe abducted him and sold him in the market of ‘Ukaz. Hakim bin Hizam radi Allahu anhu bought him for his paternal aunt, Khadijah radi Allahu anha, and after her marriage, she gifted him to the Messenger of Allah sallallahu alayhi wa sallam. Gradually, Zayd’s father came to know of this, who used to weep in grief over their separation. He, along with his brother Ka‘b, came into the presence of the Prophet sallallahu alayhi wa sallam with the ransom amount. The Prophet said, “Ask your son; if he is willing to go with you, I have no objection. But if he wishes to stay with me, then it is not possible for me to ignore his choice.” Zayd preferred to remain with the Prophet, so the Prophet, according to the custom of Jahiliyyah, announced, “From today, Zayd is my son; I am his heir and he will be my heir.” At this, Zayd’s father and uncle left content and satisfied, and from then on, Zayd began to be called Zayd bin Muhammad, until the Noble Qur’an declared the abolition of this custom. For details, see (Tabaqat Ibn Sa‘d, vol. 3, pp. 40–43 and Al-Isabah, vol. 1, pp. 245–246).

Hadith Commentary:
In the law of Islam, an adopted boy or girl holds no legal weight; they will not receive the same rights as biological children.

Hadith Commentary:
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Hazrat Zayd ibn Harithah radi Allahu anhu was the freed slave and adopted son of the Noble Prophet sallallahu alayhi wa sallam, and the Prophet had immense love for him. Similarly, Hazrat Zayd radi Allahu anhu also had a deep attachment to him.
His brother, Hazrat Jabalah ibn Harithah, narrates that he came into the service of the Messenger of Allah sallallahu alayhi wa sallam and said:
“O Messenger of Allah sallallahu alayhi wa sallam! Please send my brother Zayd with me.”
He (the Prophet) replied:
“He is present, and if he wishes to go with you (to Yemen), I will not prevent him.”
Hazrat Zayd ibn Harithah radi Allahu anhu said:
“O Messenger of Allah sallallahu alayhi wa sallam! I do not prefer anyone over you.” Thus, Hazrat Jabalah radi Allahu anhu says that he found his brother’s opinion superior and weightier than his own.
(Jami‘ at-Tirmidhi, al-Manaqib, Hadith: 3815)

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When Allah Ta‘ala intended to abolish the custom of the Age of Ignorance, He chose the adopted son of the Messenger of Allah sallallahu alayhi wa sallam himself, Hazrat Zayd radi Allahu anhu, for this purpose. Thus, after the revelation of the verse, he was called Zayd ibn Harithah instead of Zayd ibn Muhammad.
In any case, in Islamic law, an adopted child does not have such a status that he receives the same rights as real offspring.
(Wallahu a‘lam)