The series so far has mostly emphasized the continuity of the Old and New Testaments regarding belief in the one God revealed in the Scriptures. This and subsequent episodes however press home the discontinuity between the God of the Jews and the God of Christians. This discontinuity becomes obvious in the gospels where Christ's messiahship, deity and exclusive mediatorial role are affirmed. Christ said that "all things have been handed over to Me by My Father." (Matthew 11:27) He told the Jews "unless you believe that I am He (a declaration of his messiahship and deity), you will die in your sins." (John 8:24) John later declares that "whoever denies the Son does not have the Father." (1 John 2:23) Once the Son is raised from the dead, faith in Christ as the divine Messiah and only mediator between God and man is absolutely necessary for salvation. Faith in Christ is moreover the natural response of any who are TRUE sons of Abraham and Moses. Abraham saw Christ's day and was glad. (John 8:56) Moses prophesied of the coming Messiah and made obedience to His authority the very essence of true Judaism. (Deuteronomy18:18-19) Peter said that any Jew who rejected Christ would be "cut off from His people." (Acts 3:23, NIV) A fair conclusion of all these Scriptures is that Jews who reject Christ are not children of Abraham or true Jews, and Christians and Jews do NOT believe in the same God.
Sons of Abraham Follow His Example
This episode spells out the significance of the covenant God made with Abraham in Genesis 15, in light of the rest of the Scriptures. The previous episode noted that Abraham was justified by faith (Genesis 15:6), and Abraham rejoiced when he saw his perfect representative in Christ. (John 8:56) God did not make a covenant with Abraham directly but made it through his representative. These foundational planks of Judaism help answer the question "do Jews and Christians believe in the same God?' To the extent that Jews continue to relate to God in the manner of Abraham, they believe in the same God as Christians. Christ came 2,000 years ago, perfectly fulfilling the hope of Abraham, who saw Christ's day and was glad. (John 8:56) Just as Abraham believed and saw his perfect representative in Christ, albeit in types of a "smoking oven" or a "flaming torch," believers in Christ become sons of Abraham when they put their faith in the second Adam.(Galatians 3:7) The emergence of the distinctive traits of Judaism in the father of Judaism, Abraham, point to their full development and expression in Christianity, highlighting the continuity between the Old and New Testaments.
Did Abraham See Christ?
This episode focuses narrowly on the explanation of John 8:56, in which Christ notes that Abraham "rejoiced to see My day and was glad." The explanation is very pertinent to the question, "Do Jews and Christians believe in the same God?" For if the father of Judaism, Abraham, actually saw the pre-incarnate Christ, in the context of making a covenant with Yahweh, then faith in God the Father is intimately linked with God the Son. Genesis 15:6-18 describes the covenant that God made with Abraham. When two parties made a covenant both would walk in between animals split in half, pronouncing blessings and curses for keeping the covenant. Abraham did not walk in between the animals but instead saw a "smoking oven and a flaming torch." When interpreted through the words of Christ, that Abraham SAW Christ's day and was glad, Abraham evidently saw his perfect representative, Christ, making a covenant with God the Father--good reason to rejoice. Abraham is described as "ungodly" in Romans 4:3, but is commended because he believes in God who justifies the ungodly. The Abrahamic covenant then anticipates the New Covenant that Christ instituted, in which ungodly men are justified by faith in Him. So even at the very beginning of Judaism, justification by faith in Christ, albeit not explicit, affirms the basis by which sinners approach a holy God, through a perfect representative. With respect to the question then, one can certainly say that Christians and the first Jew (Abraham) believed in the same God.