Genesis 17:2

Again, when He speaks in His own person, He confesses Himself to be the Instructor: “I am the Lord thy God, who brought thee out of the land of Egypt.” Who, then, has the power of leading in and out? Is it not the Instructor? This was He who appeared to Abraham, and said to him, “I am thy God, be accepted before Me;” and in a way most befitting an instructor, forms him into a faithful child, saying, “And be blameless; and I will make My covenant between Me and thee, and thy seed.” There is the communication of the Instructor’s friendship. And He most manifestly appears as Jacob’s instructor. He says accordingly to him, “Lo, I am with thee, to keep thee in all the way in which thou shalt go; and I will bring thee back into this land: for I will not leave thee till I do what I have told thee.” He is said, too, to have wrestled with Him. …

C. Why then in Holy Scripture are we stimulated to aim at perfect righteousness? For example:“Blessed are the pure in heart, for they shall see God,” and“Blessed are the undefiled in the way, who walk in the law of the Lord.” And God says to Abraham,“I am thy God, be thou pleasing in My sight, and be thou without spot, or blame, and I will make My covenant between Me and thee, and will multiply thee exceedingly.” If that is impossible which Scripture testifies, it was useless to command it to be done.