I say, and with God's success: The scholar Mustafa al-Zarqa has previously issued a fatwa on this matter as mentioned in his fatwas, pages 563-564. A similar fatwa was issued by the European Council for Fatwa and Research, which permitted purchasing a house with an interest-based loan in non-Islamic countries based on the jurisprudential rule that necessities permit the prohibited, and based on the Hanafi opinion that dealing with usury is permissible in the land of war. The king of scholars, Al-Kasani, said in Al-Bada'i 5:192: As for the conditions for the flow of usury, one of them is that both exchanged items must be protected. If one of them is not protected, usury does not occur according to us, and according to Abu Yusuf, this is not a condition, and usury is realized. Based on this principle, if a Muslim enters the land of war as a merchant and sells a belligerent one dirham for two dirhams, or any other invalid sales according to Islamic law, it is permissible according to Abu Hanifa and Muhammad, while according to Abu Yusuf, it is not permissible. On this disagreement, the Muslim captive in the land of war, or the belligerent who converted to Islam there and did not migrate to us, if he sells to one of the belligerents. The reasoning for Abu Yusuf's opinion is that the prohibition of usury, as it is established for Muslims, is also established for non-Muslims; because they are addressed with prohibitions in the correct opinions, so making it a condition in the sale invalidates it, just as if a Muslim sold to a belligerent who is granted safety in the land of Islam. For them: The wealth of the belligerent is not protected but is permissible in itself, except that the Muslim granted safety is prevented from owning it without his consent due to the betrayal and treachery involved. If he exchanges it willingly and with his consent, this meaning is removed, so taking it becomes seizing permissible property that is not owned, and it is permissible and beneficial for ownership like seizing firewood and grass. Thus, it becomes clear that the contract here is not ownership, but rather obtaining the condition of ownership, which is consent; because the ownership of the belligerent does not cease without it, and as long as his ownership does not cease, taking it does not occur as ownership. However, if it ceases, the ownership of the Muslim is established by taking and seizing, not by the contract, so usury does not occur; because usury is a term for a benefit obtained through the contract, unlike a Muslim who sells to a belligerent who enters the land of Islam with safety; because he has obtained protection by entering the land of Islam with safety, and the protected wealth cannot be the subject of seizure, so ownership is established through the contract. And the condition of usury in the contract is corrupt...". A similar statement is found in Al-Mabsut 14:57. The Imam Muhammad  clarified the prohibition of treachery if a Muslim enters the land of disbelief with safety, saying in Al-Siyar Al-Kabir 4:1492: "If the polytheists captured a Muslim woman and secured her, then this safe person among them managed to steal her and take her to the land of Islam, he should not do that; because they owned her by securing her, so if they converted to Islam or became dhimmis, she would still be owned, and in this theft, he would betray them. Betrayal is forbidden, and if they wished to sell her to him for wine, pig, or carrion, it would be permissible for him to do so; because he takes it from them with their goodwill, so the meaning of betrayal cannot be established in it. Shams Al-A'imma Al-Sarakhsi mentioned in the explanation of Al-Siyar Al-Kabir 4:1488 some cases of the permissibility of invalid contracts, saying: "If a Muslim sold a belligerent wine and delivered it to him, and took the price, then the people of the land converted to Islam, the price remains with the Muslim; because the ruling of Islam was established in their transactions after he took the forbidden and the ruling of the contract ended in it...". As for dealing in invalid contracts between Muslims in the land of war, in Al-Mabsut 14:58: "As for two Muslim merchants in the land of war, nothing is permissible between them except what is permissible in the land of Islam; because the wealth of each of them is protected and valid, and this is established by securing in the land of Islam, and the meaning of securing does not cease by granting safety to them. Therefore, each of them is liable for the other's wealth if he damages it, and each of them only owns the other by the contract he directly engaged in, and it is not permissible to establish a contract that they did not engage in between them, such as a gift or otherwise, even if they converted to Islam and did not leave until they traded in usury, I disliked it for them, and I did not return it to them, and this is the opinion of Abu Hanifa , while Abu Yusuf and Muhammad  return it, and the ruling in it is like the ruling in the two merchants." A similar statement is found in the Indian Fatwas 3:248. The reason for the permissibility of invalid contracts between a Muslim and a belligerent is the absence of a contract between them in the land of war; because the wealth of the belligerent is owned by the Muslim by original permissibility, and it is not permissible to take their wealth without their consent due to the contract of safety that prevents us from betrayal and deception, and through these forms of contracts, their consent is realized, thus making their wealth permissible. If what has preceded is established, know that each school has its scholars who are knowledgeable about its rulings and the opinions issued from it without others. The senior scholars of the Hanafi school are unanimous on the prohibition of invalid contracts between a Muslim and a belligerent in the land of disbelief; due to the many harms that result from it, because many of the disbelieving countries have thousands, even millions of Muslims residing in them, and they suffer great harm from usurious transactions and others, and the wealth of Muslims has become in the banks of the Westerners, which they use against them. Because of this and other reasons, the fatwas of the senior scholars of the school have converged on the opinion of Abu Yusuf . The scholar and researcher Dhafar Ahmad Al-Tahanawi (d. 1394 AH) said in I'la Al-Sunan 14:414: "There is no doubt that avoiding usury, even with a belligerent in the land of war, is better, safer, purer, and more likely to be free from controversy, and this is what our teacher, the sage of the nation, has endorsed and issued a fatwa on, preferring the opinion of Abu Yusuf and the majority." Sheikh Muhammad Taqi Usmani responded in Research on Contemporary Jurisprudential Issues, page 346, regarding purchasing a house, car, or other items from interest-based banks in Europe and America, saying: "The aforementioned transaction is not permissible as it involves unlawful usury according to Sharia. Muslims, who are not few in number, should strive to find alternatives to this transaction that comply with Islamic law, such as having the bank itself be the seller on an installment basis, increasing the price of houses and others above the known price, purchasing them from sellers, and selling them to their customers at a reasonable profit. This issue should be presented to an independent committee to plan a non-usurious banking system to look into its details." The scholar Muhammad Said Al-Barhany mentioned in the margin of Al-Durar Al-Mubahah, page 73: "Muslims residing today in the lands of war... it is not permissible for them to deal with belligerents in any form..." And the dear brother Sheikh Faraz Rabbani said: "What is issued by the verified scholars of the school, including the senior scholars of Deoband like the scholar Mufti Muhammad Taqi Usmani and our teacher, the scholar Mufti Mahmood Ashraf Usmani, as well as senior scholars from the Levant, including the esteemed Sheikh Abdul Razak Al-Halabi and our teacher, the scholar Adeb Klas, and the scholar Muhammad Said Al-Barhany... is that those lands differ in reality from what the jurists have addressed, so such rulings recorded in books should not be applied to Muslims in those lands; for many reasons, including citizenship, the large number of Muslims residing there, and the confirmed harm that returns to Muslims... and others. Thus, what is issued by those whose opinions are respected among the scholars of the school is that all rulings of usury apply in the lands of disbelievers, and it is not permissible for a Muslim, whether a resident, a visitor, or a traveler, to engage in usurious contracts." And Allah knows best, and His knowledge is most wise.