How did the nation of Israel receive God's Law?
God gave the Law to Moses on Mount Sinai after Israel came out of Egypt and encamped around the mountain. Moses then came down from the mountain and delivered God's Law, including the Ten Commandments, to the nation of Israel. Thus Israel received the Law through Moses, a man.
Les explains that after Israel had come out of Egypt and crossed the Dead Sea, they encamped around Mount Sinai. God called Moses to come up into the mountain, and there God gave Moses the Law, the Ten Commandments, and all the rest of it. Moses came down off the mountain and gave the Law to the nation of Israel. Les uses this to show that God used a man, Moses, to give the Law to Israel. He then compares this with Ishmael, noting that Israel is God's earthly people with earthly promises, and everything concerning them is earthly.