All the promises of God in Him are Yes and Amen because of the finished work of Jesus Christ. Although the modern usage of the word "promises" in the English language always denotes things that are yet to be done in the future, the promises of God however are always based in the completed work of Jesus Christ. The new covenant is established on better promises. Why? Because all the promises of God in the New Covenant looks back at the completed work of Jesus Christ at the cross while the promises of God in the Old Covenant looks forward to the cross of Calvary. We can add nothing to the completed work of Jesus Christ except by saying Amen which means "I believe".