Why did God reach down and speak to Abraham?
God reached down and spoke to Abraham because, although Abraham lived in idolatry and had no knowledge of the One True God, God saw in him the potential to believe what God said. God thus communicated with him, appearing in physical form more than once, making him the example of justification by faith alone.
Les explains that Abraham is the epitome of a man of faith, who was justified by doing nothing and meriting nothing. Abraham had been raised and was living in abject idolatry, with no knowledge of the One True God. Yet God saw in that man the potential to believe what He said, so He reached down, spoke to him, and appeared to him in a physical form, coming down and communicating with him more than once. Paul, by inspiration, goes back to Abraham as the perfect example of what it means to be justified—made totally righteous by faith, and faith alone, plus nothing. The law cannot produce heirs; it works wrath, and grace is not license.