Irenaeus

And that the Saviour received first-fruits of those whom He was to save, Paul declared when he said, "And if the first-fruits be holy, the lump is also holy," teaching that the expression "first-fruits" denoted that which is spiritual, but that "the lump" meant us, that is, the animal Church, the lump of which they say He assumed, and blended it with Himself, inasmuch as He is "the leaven."