Was Abraham's call an act of God's grace?
Yes, Abraham's call was an act of God's grace. God reached down to one man, Abraham, out of an idolatrous family and city of Ur, just as He did with Saul on the road to Damascus. It was God's gracious initiative that called Abraham to leave and go to a land God would show him.
Les explains that the whole world, including Abraham's family, was steeped in idolatry. Into that idolatrous home and pagan city of Ur, God in His grace reached down to one man, Abraham, much like He did with Saul on the road to Damascus. God told Abraham in Genesis 12:1 to leave his family, his city, and his father's house and go to a land God would show him. Abraham did it in response to faith. Les notes that salvation is profound and complex, yet simple enough for a child to understand when first entering in; as believers grow in faith, they realize how deep it is and that we will never plumb its depths.