The apostle wrote: "Whatever was written in earlier times was written for our instruction, so that through perseverance and the encouragement of the Scriptures we might have hope." (Romans 15:4)Dr. Ray Stedman, in his book Man of Faith wrote, "There is a simple secret that ties together the Old and the New Testaments and makes the study of the Old Testament a never-ending delight. The Old Testament is designed as a picture book, illustrating with fascinating stories the spiritual truths presented in the New Testament. This is especially true of the book of Moses and the book of Joshua; for in the life histories of men like Abraham . . . we have symbolized for us the progress of spiritual growth."Abraham is set forth in Scripture as the father of the faithful and the "friend of God." His spiritual experience is presented in four far-reaching crises in which he was tested and matured. These are his responses to God's call to leave his country and relatives; his separation from his nephew Lot, leaving him completely isolated from all kindred in a land in which he was a stranger; his response to God's rejection of Ishmael and trust in His promise that Sarah would one day bear him a son; and his willingness to offer up Isaac, believing that he would be resurrected.Isaac was the child of promise, and though little is told of his long life, he remained faithful to the Lord in spite of many difficulties, and illustrates for us how a man can triumph over physical ailments and family discord.Of these Old Testament characters Paul wrote, "Now these things happened to them as an example, and they were written for our instruction, upon whom the ends of the ages have come" (1 Corinthians 10:11).