Where did the children of Israel receive the Law?
The children of Israel received the Law at Mount Sinai. The context explains that after Moses led them out, they went and received the Law at Mount Sinai, which occurred 430 years after Abram left Haran for Canaan, as discussed in Galatians chapter 3.
Les teaches that the 430 years transpired from the time Abram left Haran and went down into Canaan until Moses led the children of Israel out, and they went and received the Law at Mount Sinai. He was teaching from Galatians chapter 3, moving from verse 17 to verse 18, where the inheritance is discussed.
And this I say, that the covenant, that was confirmed before of God in Christ, the law, which was four hundred and thirty years after, cannot disannul, that it should make the promise of none effect.