Ibn Majah

Benefits and Issues:

➊
A slave cannot migrate without the permission of his master, because in doing so, the master would be deprived of his right to take service from him.

➋
The buying and selling of slaves and livestock is permissible in the form of exchange with a difference in quantity. For example: it is permissible to give or take two sheep of a lower quality in exchange for one excellent sheep, or to exchange two lambs for one sheep. However, the exchange of agricultural produce with a difference in quantity is not permissible. For example: exchanging one maund of excellent wheat for one and a half maunds of inferior wheat is not permissible. (See: Sunan Ibn Majah, Hadith: 2252)

➌
The Prophet (sallallahu alayhi wa sallam) was not the knower of the unseen (‘alim al-ghayb).
Knowledge of the unseen belongs only to Allah.

(1) From this hadith, it is understood that the pledge of allegiance (bay‘ah) by a slave without the permission of his master is not permissible.

(2) This hadith also indicates the great noble character (makarim al-akhlaq) of the Messenger of Allah (sallallahu alayhi wa sallam) and his kindness towards common people, in that he did not wish to send the slave back so that he would not be disheartened, nor would the purpose for which he had come be disrupted. Thus, the Prophet (sallallahu alayhi wa sallam), showing immense kindness, purchased him so that his objective would be fulfilled.

(3) From this blessed hadith, the ruling is also derived that it is permissible to sell one slave in exchange for two slaves, whether the price is the same or there is a difference in price. The same ruling applies to all animals and livestock. The majority of scholars hold the permissibility of this sale, whereas Imam Abu Hanifah and the scholars of Kufa consider it impermissible.

(4) This hadith also establishes that the Messenger of Allah (sallallahu alayhi wa sallam) was neither the knower of the unseen (‘alim al-ghayb) nor was he granted knowledge of the unseen (‘ilm al-ghayb) as a gift. This is why he accepted the pledge of allegiance from the slave who had come without his master’s permission. Similarly, after this incident, the Prophet (sallallahu alayhi wa sallam) would ask every person who came to pledge allegiance whether he was a slave.

(5) The Messenger of Allah (sallallahu alayhi wa sallam) was cautious, which is why he would ask those coming to pledge allegiance.

(6) A slave is not the master of his own will. He is bound by the command of his master; therefore, the Islam of a slave is valid and accepted, but the pledge of allegiance for migration (hijrah), jihad, etc., is not valid. It is possible that the master may not grant permission, as occurred in the aforementioned incident. It is a separate matter that the Prophet (sallallahu alayhi wa sallam), in consideration of the pledge for migration, purchased him, but this would not be possible for every slave.

(1) This blessed hadith clearly indicates the noble character of the Messenger of Allah (sallallahu alayhi wa sallam) and his immense kindness. That is why he did not return the slave, even though his owner arrived. He fulfilled the slave’s intention, that is, his desire to migrate. He did not deprive him of the companionship of the Prophet, and bought him in exchange for two slaves.

(2) From this hadith, it is also understood that the sale (buying and selling) of one slave in exchange for two slaves is permissible, whether their prices are equal or different. There is consensus among the scholars on this matter, but the condition is that the sale must be immediate (cash). It should not be deferred on either side. The same ruling applies to all animals, whether one slave is exchanged for two slaves, or one camel for two camels.

(3) This blessed hadith also establishes that the original state of human beings is freedom and liberty. That is why the Messenger of Allah (sallallahu alayhi wa sallam) did not ask the incoming slave whether he was free or a slave, but rather accepted his pledge of allegiance according to this principle.

(4) This blessed hadith is also a clear proof of this important issue: that the Messenger of Allah (sallallahu alayhi wa sallam) did not possess knowledge of the unseen (ilm al-ghayb) at all. If he had knowledge of the unseen, he would have immediately known that the person coming was a slave, and he would also have certainly known that his owner was following behind him. Furthermore, he would never have asked anyone coming to pledge allegiance in the future whether he was free or a slave. The Messenger of Allah (sallallahu alayhi wa sallam) only knew what Allah, the Exalted, informed him of.

(5) It is understood that in the mutual buying, selling, and exchange of animals, disparity (in number or value) is permissible, because there is often a difference in the status of animals, as if they are of different kinds. And when the kinds are different, disparity is permissible. One camel may be worth fifteen thousand, while another camel may be worth several hundred thousand, so animals are considered as if they are of different kinds. The Shariah, in its rulings, also takes into account people’s necessities, even if a subsidiary principle has to be changed; the absence of hardship is a fundamental principle.

Hadith Commentary: Benefits and Issues: Since the Messenger of Allah (sallallahu alayhi wa sallam) did not possess knowledge of the unseen, he (sallallahu alayhi wa sallam) accepted the pledge of allegiance (bay‘ah) from the slave upon his migration, even though a slave cannot migrate without the permission of his master. However, since he (sallallahu alayhi wa sallam) had already accepted the pledge, he did not deem it appropriate to return him to his master. And, based on noble character, he (sallallahu alayhi wa sallam) purchased him from his owner in exchange for two slaves. The sale of animals with an increase or decrease in price, when done hand to hand (spot transaction), is unanimously permissible. And in the case of a deferred payment, according to the Imams of Hijaz (Malik, Shafi‘i, Ahmad) and the majority, it is permissible, because the Prophet (sallallahu alayhi wa sallam), in preparation for a military expedition, took one camel on deferred payment in exchange for two camels. However, according to the Hanafi Imams, the sale of an animal in exchange for another animal on deferred payment is not permissible. And the hadith from which they deduced this means that if both sides are deferred, then it is not permissible.

Explanation:
1:
From this hadith, it is understood that it is permissible to buy and sell one slave in exchange for two slaves,
with the condition that this transaction is conducted in cash.
It is also understood from the hadith that it is necessary to inquire about the status of servitude or freedom from a person who comes for allegiance (bay‘ah),
because if he is a slave, it is not valid to take allegiance from him.