Exodus 22:21

Neither vex a stranger. This precept against the oppression of foreigners is most significant, since it is unlikely that such a provision was ever made in the laws of other ancient countries. While elsewhere foreigners might be harassed, the Mosaic law forbade the Hebrews to treat strangers thus (Ex. 23:9; Lev. 19:33). Instead, they were to “love” strangers (Lev. 19:34). Their own experience as “strangers in the land of Egypt” was to be a constant reminder that they were to deal kindly with these foreigners (Deut. 10:19). This kindness to foreigners was also to be given in the hope that they might be made proselytes (see Acts 13:43). Although the Hebrews were to remain separate from other nations in matters of religion, they were not to isolate themselves to the extent that they would fail to show kindness to a stranger.