Where did God give Paul the doctrines of grace?
God gave Paul the doctrines of grace at Mount Sinai in Arabia, the same place where He had given the Law to Moses. Paul later refers to this in Galatians chapter 1 as the revelation of the mysteries, showing that God directly revealed these truths to him there.
Les teaches that after Paul escaped Damascus by being let down the wall in a basket at night, he went from Damascus down to Mount Sinai in Arabia, as Paul tells us later in Galatians chapter 1. That is the very same place where God originally gave the Law to Moses. Now God is giving to this man the whole doctrines of grace. Paul will usually refer to this as the Revelation of the Mysteries. So the location was Mount Sinai in Arabia, and the content was the doctrines of grace revealed directly by God.