Two Testaments, One Gospel, One True People of God

I recently read a shocking claim, that the two testaments teach two different religions! (1 Question, Shannon & Postovich, p.4). How many Christians think this?  I hope not many, since it only takes a simple familiarity with Scripture to know that the two testaments teach one gospel and one people of God.

God first announced the gospel in Genesis 3:15, not John 3:16. Abraham was saved by believing it (Genesis 15:6). The ancient people knew that God was sending a savior who would crush Satan's head and trade curse for blessing. Depth of detail in the gospel increased as the prophets wrote, and the greatest clarity came when Jesus arrived, but the essential kernel of the gospel never changed. Salvation has always been a free gift, always been received by faith alone, and always been brought about by the Son of God.

In the same way, there has always been just one true people of God. Paul says that those who were only Jews outwardly were never true Jews (Romans 2:28-29). John said that new birth has never been by bloodline (John 1:13).

The OT prophets foretold the current age. Gentiles would be baptized by the Spirit (Joel 2:28-32, Acts 11:15-17). God would send salvation's light to the Gentiles (Isa. 42:6, Acts 13:47). God would restore the Davidic line through Christ in order to bring Gentiles in (Amos 9:11, Acts 15:14-18). The Christian Church is God's chosen people, holy nation, and peculiar possession (Deut. 7:6, 1 Pe. 2:9). 

​This does not mean that God has 100%, utterly cast aside the Jews. God has not rejected His elect remnant (Romans 11:1-5). God's gifts and calling of the Jews are irrevocable (11:29). God will keep His promises to Abraham. But the Jews need to be saved (11:14), because they stand rejected by God in their unbelief (11:15). They have been broken off from the symbolic olive tree of God's people (11:17), unless by God's grace they repent (11:23).

God certainly changed much in the aftermath of Jesus' resurrection. The symbolic ceremonial laws of Moses were all fulfilled by Christ, and Moses' civil laws only illustrate principles of justice. Churches should be led by pastor-teachers now, not priests, and served by deacons, not Levites. But never believe that we Christians live in a "parenthesis"! We are the continuation of what God officially began in Genesis 12.  The Bible may have two testaments, but there is only one God, one Gospel, one faith, one hope, and only one true people of God throughout the ages, regardless of denominations.

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