What changes in God's dealings with people?
What changes is not God Himself but the responsibilities He places on the human race. God remains the same from eternity past to eternity future; only His requirements and dealings with people shift. His grace stays evident throughout, even when people live under different programs or economies.
Les teaches that God has never changed, from eternity past nor into eternity future; it is the same God. The only thing that changes is His responsibilities that He puts on the human race. Les connects this to Romans 5:20, where Paul writes that where sin abounded, grace did much more abound. Even though the context is the Jewish economy under the Law, God's grace has always been evident. Adam and Eve did not run to God after sinning; God went looking for them on the basis of grace and brought them back into relationship with Himself. Israel repeatedly turned from Jehovah, yet God returned to them by His grace. In the same way, the four women in the genealogy—including Tamar, Rahab, and Ruth—were in direct opposition to what God had instructed, yet in His mercy and grace He brought them into renown by including them in the genealogy.
Moreover the law entered, that the offence might abound. But where sin abounded, grace did much more abound: