Romans 11:16

And we have the strongest reason for believing in this reconversion of the Jews. Their forefathers were the first recipients of the promise, and what they were it is only natural to hope that their descendants will be. When a piece of dough is taken from the lump to make a consecrated cake, the consecration of the part extends over the whole; and the character which is inherent in the root of a tree shows itself also in the branches. So we may believe that the latter end of Israel will be like its beginning. The consecration that was imparted to it in the founders of the race we may expect to see resumed by their descendants, even though it is for a time interrupted.

The firstfruit ... the lump. — The allusion here is to the custom, described in Numbers 15:19, of dedicating a portion of the dough to God. The portion thus taken was to be a “heave-offering” — i.e., it was to be “waved,” or “heaved,” before the Lord, and was then given to the priest.