Where did Moses receive the Law and the Ten Commandments?
Moses received the Law, including the Ten Commandments, on Mount Sinai. After Israel came out of Egypt and encamped around the mountain, God called him up and gave him the Law and all the rest. Moses then descended and delivered God's Law to the nation of Israel.
The teaching explains that Israel had come out of Egypt, crossed the Dead Sea, and was encamped around Mount Sinai. There God called Moses to come up into the mountain, and He gave Moses the Law, the Ten Commandments, and all the rest of it. Moses came down off the mountain and gave the Law to Israel. The context uses Mount Sinai as an allegory of the two covenants: the one from Mount Sinai genders to bondage, which is Hagar, while Israel is God's earthly people with earthly promises.