by it, he meant: there is no migration after the Conquest from a land that has already been conquered. His statement to Safwan, "Migration has indeed ceased," refers to Makkah, because migration is the departure from the land of the disbelievers, so once it is conquered, it no longer remains a land of disbelievers, and thus no migration remains from it. This applies to every land that is conquered; migration from it does not remain, rather, the migration is toward it. Once this is established, people in relation to migration are of three types. The first is one for whom it is obligatory: this is the one who is able to perform it and cannot manifest his religion, or cannot fulfill the obligatory duties of his religion while residing among the disbelievers. For him, migration is obligatory, based on the saying of Allah the Almighty: "Indeed, those whom the angels take [in death] while wronging themselves, [the angels] will say, 'In what [condition] were you?' They will say, 'We were oppressed in the land.' They will say, 'Was not the earth of Allah spacious [enough] for you to emigrate therein?' For those, their refuge is Hell – and evil it is as a destination." This is a severe threat indicating the obligation. Also, because upholding the obligatory duties of one's religion is mandatory upon those capable of it, and migration is a necessity for the obligation and completes it; whatever is required to complete an obligation is itself obligatory. The second is one for whom there is no migration: this is the one who is incapable of it, either due to illness, coercion to remain, or weakness, such as women, children, and their likes. For him, there is no migration, based on the saying of Allah the Almighty: "Except for the oppressed among men, women, and children who cannot devise a plan nor are they directed to a way. It is expected that Allah will pardon them, and Allah is ever Pardoning and Forgiving." It is not even described as recommended, because it is not within one's capability. The third is one for whom it is recommended but not obligatory: this is the one who is capable of it but is able to manifest his religion and perform it in the land of disbelief. It is recommended for him so that he may be able to wage Jihad against them, increase the number of Muslims, assist them, and rid himself of being counted among the disbelievers, mixing with them, and seeing the forbidden acts among them. It is not obligatory for him, because it is possible to perform the obligatory duties of his religion without migration. Al-Abbas, the uncle of the Prophet, peace and blessings of Allah be upon him, resided in Makkah while being Muslim. We have narrated that when Nu'aym al-Nahham intended to migrate, his people, the Banu Adi, came to him and said: "Stay with us, and you remain upon your religion; we will protect you from whoever wishes you harm, and suffice us as you have been doing." He used to take care of the orphans and widows of Banu Adi, so he delayed his migration for a while and then migrated later. The Prophet, peace and blessings of Allah be upon him, said to him: "Your people were better for you than my people; my people cast me out and wanted to kill me, while your people protected you and defended you." He replied: "O Messenger of Allah, rather your people cast you out for the obedience of Allah and Jihad against His enemy, whereas my people discouraged me from migration and the obedience of Allah," or words to that effect.

Section: He said, "Whoever enters the land of the enemy with a security pact (aman), he shall not betray them regarding their wealth, nor shall he deal with them in usury (riba)."

As for the prohibition of usury in the Dar al-Harb (land of war), we have already mentioned it in the Book of Usury, in addition to the fact that the saying of Allah the Almighty: "And has permitted trade and has forbidden interest," and the rest of the verses and reports indicating the prohibition of usury are general, encompassing usury in every place and time. As for betraying them, it is forbidden because they only granted him the security pact on the condition that he does not betray them and that he keeps them safe from himself. Even if this is not explicitly mentioned in the wording, it is understood in the meaning. Therefore, whoever comes to us from them with a security pact and then betrays us is considered a breaker of his covenant. Once this is established, it is not lawful for him to betray them because it is treachery, and treachery is not appropriate in our religion. The Prophet, peace and blessings of Allah be upon him, said: "Muslims are bound by their conditions." If he betrays them, steals from them, or borrows something, he is obligated to return what he has taken to its rightful owners. If the owners come to the land of Islam with a security pact or faith, he returns it to them; otherwise...