Christianity since “in the beginning”

 That's a good way to summarize a very significant theological framework within Christianity, particularly in some Protestant traditions. You're touching on a key concept in Christian thought: the progression of God's relationship with humanity through different eras or dispensations.

Here's a breakdown of the key ideas you've mentioned:

 * God and Israel: Many Christians believe that after the creation and fall of humanity, God chose the nation of Israel to be his special people. Through them, he revealed his laws and made promises (the covenants). Israel's purpose, in this view, was to be a "light to the nations" and prepare the way for the Messiah, who would ultimately fulfill these promises.

 * The Church Age: This is a term used to describe the current period, which began with the coming of Jesus Christ, his death and resurrection, and the establishment of the Church. The belief is that the "gospel"—the good news of salvation through Jesus—is now to be shared with all people, not just the nation of Israel. In this view, the Church is the new body of believers, made up of both Jews and Gentiles, and is the primary instrument for spreading the gospel today.

This perspective highlights a theological transition from a focus on one specific nation (Israel) to a universal, global mission through the Church. It's a way of understanding how the story of God's work unfolds from the Old Testament to the New Testament.