Malachi 3:1: 'Behold, I send my messenger, and he will prepare the way before me. And the Lord whom you seek will suddenly come to his temple; and the messenger of the covenant in whom you delight, behold, he is coming, says the Lord of hosts.'
The covenant with Abraham included the promise that he would found a great nation, and the story of Isaac's conception and birth against the odds point to the compassion and power of God