Is trade permitted for non-Muslims from hostile lands into Hijaz?

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Trade is permissible for them to enter Hijaz for commerce. This is established by the precedent that Christians used to trade to Medina during the time of Umar (may Allah be pleased with him). Umar issued a ruling that they should only be subjected to a single instance of tariff (*'ushr*) per year. Furthermore, they are not permitted to stay for more than three days, according to what is narrated from Umar (may Allah be pleased with him), after which they must depart. This ruling regarding entry permission is analogous to the ruling concerning the entry of people of war (*Ahl al-Harb*) into the Abode of Islam.