Lesson Five: Oneness in Christ
The Foundation the Church Is Built On
A Promise That Was Always Meant to Reach Everyone
Long before there was a church, God made a promise to Abraham that carried within it the seed of a much larger story.
All peoples on earth. From the very beginning, the blessing given to Abraham was never intended to stay contained within one family or one nation. It was always meant to flow outward, eventually reaching every people group on the earth. The church, built centuries later, is the outworking of that ancient promise, not a departure from it.
Grafted Into the Same Root
Paul describes exactly how this promise reaches beyond Israel to include the nations, using the image of an olive tree with its cultivated root.
This is the picture of oneness the church is actually built on, not a new tree planted separately, but wild branches grafted into an already existing root, drawing life from the same source Israel has always drawn from. Gentile believers were brought in by grace, not because they earned a place or improved on what was already there, but purely as a gift.
The Church's True Foundation
Whatever oneness the church experiences is not built on shared culture, shared preference, or even shared nationality. It is built on a single foundation.
Christ himself is the cornerstone, the single point every other part of the structure is measured against and aligned to. This is why the unity of the church can hold together people of vastly different backgrounds, languages, and histories. The unity was never meant to come from sameness among the people. It comes from every person being joined to the same cornerstone.
One Body, Many Parts
Paul develops this picture further, describing the church not as a uniform mass but as a body made of genuinely different parts working together.
Oneness in scripture never means the erasure of difference. It means many distinct parts, joined at the same root and the same cornerstone, moving together for the same purpose. This is the picture the church was always meant to embody, unity without uniformity, diversity without division.
Living This Out
This lesson asks what actually holds a church, a small group, or a believer's own life together. Is it shared preference and comfort, which will always eventually run out, or is it genuine oneness with Christ as the cornerstone, the same root every branch, wild or original, draws its life from? That question shapes everything about how believers relate to each other going forward.