What is the Biblical Basis for Replacement Theology, the shifting of the birthright from Israel to the Church?

I'm new to the website, but found the discussion of birthright to be edifying and certainly consistent with church history. In relation to @pehkay's statement, "Furthermore, in the New Testament the birthright is shifted from Israel to the church" in that discussion, my question is this: *Is the shifting of the birthright from Israel to the Church, of God or of man, and how does Scripture support your answer?*