The agricultural practice of grafting joining a shoot or bud to a growing plant so they grow together into a new plant-was well-known in the ancient world. It was usually done to promote new growth and increased fruit production among similar plant species. Grafting was a faster way to get a mature plant than starting from seeds. Often a branch from a cultivated tree would be grafted onto an already established wild tree, and the wild tree
would then produce better fruit in greater quantity. As an image, grafting appears only once in Scripture, although it also reminds the reader of similar imagery related to vines, branches, and roots.
In Romans 11, the image of grafting is used to illustrate the relationship between Israel and Gentile believers. Gentile believers had been “grafted” into the “olive tree” and were now part of God’s chosen people. They were not a separate nation but all one chosen people saved by God’s grace. The whole church benefited from their presence, just as the whole tree benefits from a grafted branch. The nation of Israel could grow bigger and stronger and be more productive with the inclusion of Gentile believers. In addition, the grafted-in branches could enjoy the benefits of Israel’s long history and the established roots of God’s previous interactions with his people. They were not a vulnerable young plant, but part of a vibrant, thriving tree. As a result, more fruit would come from the grafted plant than from either of the two original plants.
But Paul reminded Gentiles not to think they were better than the original branches: “Some of the olive branches have been broken off, and you, a wild olive branch, have been grafted in their place. You get your nourishment from the roots of the olive tree. So don’t brag about being better than the other branches. If you brag, remember that you don’t support the root, the root supports you” (Rom 11:17-18). Some Gentile believers had a sense of superiority over their Jewish brothers and sisters. Paul reminded them that they had been granted their position in God’s kingdom by God’s grace, not by their own effort, just as a branch cannot graft itself onto a tree. Paul goes on to remind Gentile believers that if God did not spare the original branches that failed to produce fruit, he would also not spare them. The penalty for not bearing fruit was the same for both Jews and Gentiles: being burned in the fire (Matt 13:40; John 15:6).