What is the Mosaic system in relation to Israel?
The Mosaic system is the religion God gave specifically to the nation of Israel, not to the world, through Moses around 1500 B.C. It became Israel's national religion, closely tied to the Jewish people though not identical to Jewish racial identity.
Les explains that when Moses comes on the scene about 500 years later, around 1500 B.C., God gives the law not to the world but to the nation of Israel. That begins the institution of the racial people of Israel, and God gives them their religion—the Mosaic system. From that point, the Jew and his religion are almost inseparable, yet separate: a Jew can embrace another religion or turn his back on Judaism and still be a Jew. Gentiles can embrace Judaism and become Jews religiously, but never racially, because Scripture divides the human race into Jew and Gentile, and only a Jew is considered a Jew in Scripture. Israel itself began when God called Abraham out of Ur and idolatry and gave him covenant promises.