To be in Christ is to do his work. To do God's work is to "believe in him whom He hath sent."
In EJ Waggoner's sweeping overview of the history of God's people, God reveals as far back as the Old Testament the same gospel which Christians believe today. From Abraham to today's reader, all who believe are under the everlasting covenant.
The author had a vision of "Christ crucified... and to me was revealed for the first time in my life the fact that God loved me, and that Christ gave Himself for me personally. It was all for me." According to Waggoner, one line runs through the Bible - God's everlasting covenant.
Share in the company of the great patriarchs and prophets as God reveals the blessed hope of all Christians to them who were willing to be used for his glory.
The same line that runs through the Bible will now be made visible - God's everlasting covenant between Himself and you.