A “stranger,” in the technical sense of the term, may be defined to be a person of foreign, i.e. non-Israelitish, extraction resident within the limits of the promised land. He was distinct from the proper “foreigner,” inasmuch as the latter still belonged to another country, and would only visit Palestine as a traveller: he was still more distinct from the “nations,” or non-Israelite peoples. The term may be compared with our expression “naturalized foreigner.” The terms applied to the “stranger” have special reference to the fact of residing in the land. The existence of such a class of persons among the Israelites is easily accounted for the “mixed multitude” that accompanied them out of Egypt, (Exodus 12:38) formed one element the Canaanitish Population, which was never wholly extirpated from their native soil, formed another and a still more important one captives taken in war formed a third; fugitives, hired servants, merchants, etc., formed a fourth. With the exception of the Moabites and Ammonites, (23:3) all nations were admissible to the rights of citizenship under certain conditions. The stranger appears to have been eligible to all civil offices, that of king excepted. (17:15) In regard to religion, it was absolutely necessary that the stranger should not infringe any of the fundamental laws of the Israelitish state. If he were a bondman, he was obliged to submit to circumcision, (Exodus 12:44) if he were independent, it was optional with him but if he remained uncircumcised, he was prohibited from partaking of the Passover, (Exodus 12:48) and could not be regarded as a full citizen. Liberty was also given to an uncircumcised stranger in regard to the use of prohibited food. Assuming, however, that the stranger was circumcised, no distinction existed in regard to legal rights ha between the stranger and the Israelite; to the Israelite is enjoined to treat him as a brother. (Leviticus 19:34; 10:19) It also appears that the “stranger” formed the class whence the hirelings were drawn; the terms being coupled together in (Exodus 12:45; Leviticus 22:10; 25:6,40) The liberal spirit of the Mosaic regulations respecting strangers presents a strong contrast to the rigid exclusiveness of the Jews at the commencement of the Christian era. The growth of this spirit dates from the time of the Babylonish captivity.
–Smith's Bible Dictionary