The Parable of the Olive Tree is a complex extended allegory recounted in Chapter 5 of the Book of Jacob, the third book of the Book of Mormon. Jacob notes that his readers would know the parable from the works of the prophet Zenos, but these works are now lost, so modern readers only know the parable through Jacob's repetition of it.
The master of a vineyard grew a tame olive tree, but in time it grew old and began to decay. In hopes of saving it he pruned it, dug the ground and nourished it. In time some new branches appeared, but the top of the tree began to perish. So the master of the vineyard instructed his servant to cut off the decayed branches, and replace them with grafts of wild olives. Meanwhile, natural branches of the tree were transplanted to other parts of the vineyard. In time the original tree, now with wild olive branches grafted onto it, grew to give good fruit. Those natural branches of the original tree that were transplanted into poor soil also grew to give good fruit. However, a natural branch of the original tree that was transplanted into good soil grew to give a mix of good and poor fruit. The master of the vineyard instructed his servant to cut off the branches of this tree that gave poor fruit, and burn them. However, the servant suggested to that master that with further care this tree too might bring forth good fruit. And so the master and his servant worked diligently at nourishing all the trees.
After a long time the master and servant returned to the vineyard, and found that all trees, both the original and the transplants, had failed, and had all grown only poor fruit. Bitterly disappointed, "the Lord of the vineyard wept, and said unto the servant: What could I have done more for my vineyard?" (Jacob 5:41). The master determined to burn all the trees in the vineyard, since all had given only evil fruit. Again the servant begged for clemency, and the master was persuaded, being reluctant to lose the vineyard he loved so much. The master decided to cut out those branches of wild olives that he had grafted onto the original tree that gave the most bitter fruit, and replace them with branches from the daughter trees that had grown from the previously transplanted cuttings. The master hoped that by bringing the branches and roots of the original tree back together, they would grow good fruit.
The master and his servants worked hard in the vineyard. They cut out the branches that brought forth evil fruit and burnt them, and pruned and nourished the trees, and dug the ground. After much hard work, there was no longer any bad fruit in the vineyard. "And it came to pass that when the Lord of the vineyard saw that his fruit was good, and that his vineyard was no more corrupt, he called up his servants, and said unto them: Behold, for this last time have we nourished my vineyard; and thou beholdest that I have done according to my will; and I have preserved the natural fruit, that it is good, even like as it was in the beginning. And blessed art thou; for because ye have been diligent in laboring with me in my vineyard, and have kept my commandments, and have brought unto me again the natural fruit, that my vineyard is no more corrupted, and the bad is cast away, behold ye shall have joy with me because of the fruit of my vineyard." (Jacob 5:75).
The parable ends with a warning from the master of the vineyard that the next time the vineyard grows poor fruit, he will simply gather in the good fruit, throw away the poor fruit, and set the vineyard to flames.
The parable is an allegory of the relationship between Jesus Christ, the world, and men. The master of the vineyard is Jesus, the vineyard is the world, and the olives represent the lives and works of men. Along with many stories and parables, the parable of the olive tree can be interpreted into your own life and you substitute the tree, olives, branches, for different things in your life.
Here, the original tree appears to represent the nation of Israel. The wild olive branches grafted on to the original tree represent Gentile nations called to the message of Christ. The transplanted branches that gives good fruit and poor fruit represents the House of Lehi fleeing to the New World, giving rise to the good fruits of the Nephites and poor fruits of the Lamanites. The bringing of the branches and roots back together represent the gathering of all the scattered tribes of Israel back to God. God can be seen as the Lord of the vineyard, and the servant intervening with the master not to destroy the vineyard can be seen as Jesus.