Thus, they cut branches from the natural mother tree which had become wild and grafted them into the three transplanted branches in the nethermost parts of the vineyard. They also took parts of the transplanted branches and grafted them back into the mother tree. This is probably the part of the parable through which we are now passing. The Gentile Christians from the wild olive tree turned out to have a strain of Israelite blood in them, and they have joined the true Church of the latter days and are giving of their strength to the Lamanites and other Israelites who are being converted in the Pacific and the Orient. Eventually, these will combine to give strength to the Jews when they are converted and also give strength to the lost tribes when they return. This amalgamation of all scripture and the final gathering of Israel are probably the events referred to in these two verses, 55 and 56.
During this pruning and grafting process the master said his servant was not to destroy the wild (Gentile) branches except those which were the most bitter. The roots (or scriptures) and the natural branches of Israel were to be kept alive among the Gentiles that hopefully they might be preserved and induced to bring forth good fruit. The plan was to nourish all the trees of the vineyard, trim up the branches, and cut out the dead wood so it could be burned.