God created the world and created us to serve and enjoy him and the world he had made. But human beings turned away from serving him; they sinned and marred themselves and the creation. Nevertheless, God promised to not abandon them (though it was his perfect right) but to rescue them, despite the guilt and condemnation they were under and despite their inveterately flawed hearts and character. To do this, first God called out one family in the world to know him and serve him. Then he grew that family into a nation; entered into a binding, personal covenant relationship with them; and gave them his law to guide their lives, the promise of blessing if they obeyed it, and a system of offerings and sacrifices to deal with their sins and failures. However, human nature is so disordered and sinful that, despite all these privileges and centuries of God’s patience, even his covenant people — who had received the law, promises, and sacrifices — turned away from him. It looked hopeless for the human race. But God became flesh and entered the world of time, space, and history. He lived a perfect life, but then he went to the cross to die. When he was raised from the dead, it was revealed that he had come to fulfill the law with his perfect life, to offer the final sacrifice, taking the curse that we deserved and thereby securing the promised blessings for us by free grace. Now those who believe in him are united with God despite our sin, and this changes the people of God from a single nation-state into a new international, multiethnic fellowship of believers in every nation and culture. We now serve him and our neighbor as we wait in hope for Jesus to return and renew all creation, sweeping away death and all suffering.
— Timothy Keller. Preaching: Communicating Faith in an Age of Skepticism. Viking, 2015. pp. 58–59.