One of the reasons I love the Reformed tradition is that it teaches that the whole Bible is for the church, not just the New Testament, or the portions of the Old Testament that sound like Jesus. I believe that the Reformed tradition is the biblical position, but I also recognize that the Bible is what reforms the Reformed. However, the beauty of the Bible is expounded wonderfully in the Reformed tradition seeing a single covenant of grace from creation to recreation (and I enjoy it because it includes our children, like God does). So anyway, here is a little bit of Calvin,
“Let us then lay it down confidently as a truth which no engines of the devil can destroy–that the Old Testament, or covenant which the Lord made with the people of Israel, was not confined to earthly objects, but contained a promise of spiritual and eternal life, the expectation of which behoved to be impressed on the minds of all who truly consented to the covenant…For, even now, the only kingdom of heaven which our Lord Jesus Christ promises to his followers, is one in which they may sit down with Abraham, and Isaac, and Jacob…thus [Christ] giving a sure earnest, that everything which he did and suffered in the purchase of eternal salvation, belonged to believers under the Old Testament just as much to us.” Institutes, II.x.23.
Christ is the hinge, the fulcrum, the bond, the glue, the fullness, the linchpin, holding the covenant of grace together. For all those who have believed the Gospel, whether its promise like Abraham (Hebrews 11:9-10), or in its fulfillment like you and I (Galatians 3:7-9), we are of the same covenant (Galatians 3:14). When a Christian dies, and enters into glory with Christ, he will see his father Abraham who also entered God’s house by the blood of the Son. Your family history, therefore, is much longer, and more detailed than you know.