What does it mean that Israel came under the Law?
Coming under the Law meant God gave Israel a distinct set of circumstances after about 500 years from Abraham. It was the Ten Commandments, the ritualistic law, the priesthood, and the temple. For the first time the human race had something written as a criteria of behavior, and God distinctively told Israel how to operate.
Les explains that Israel coming under the Law was a period when God dealt with that nation in a way He never had before. After calling Abraham out of the pagan nations, God turned His back on the other nations and dealt with Israel. About 500 years later, He gave that little nation yet another different set of circumstances: the Law. Never before had the human race anything written for a criteria of behavior. God now gave Israel the Ten Commandments, the ritualistic law, the priesthood, and the temple. It was a distinctive time when God told the nation of Israel how to operate.