How long has God been moving Israel toward the appearance of the Messiah?
Ever since Genesis chapter 12, God has been continuously moving the nation of Israel forward to the time when the king could make his appearance. The Abrahamic covenant contained the promise of a nation, land, government, and Messiah, and the law was later given to prepare Israel for that covenant's fruition.
Les teaches that God has been continuously moving the nation of Israel forward from Genesis chapter 12 until the time the king could make his appearance. Matthew's genealogy goes back only to Abraham because Matthew depicts the Messiah as the king. The Abrahamic covenant already contained, in latent form, the promise of a nation of people, a geographical land, and a government provided by the Messiah, the Son of God, Israel's king. When Israel later received the law in Exodus, its purpose was to prepare the nation for the fruition of that covenant, making her a prepared people through God's chosen system of law.
Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father’s house, unto a land that I will shew thee: