Augustine of Hippo

For it is by similitude, and not by any personal propriety, that He is thus called a vine; just as He is also termed a sheep, a lamb, a lion, a rock, a corner-stone, and other names of a like kind, which are themselves rather the true ones, from which these are drawn as similitudes, not as realities. But when He says, "I am the true vine," it is to distinguish Himself, doubtless, from that vine to which the words are addressed: "How art thou turned into sourness, as a strange vine?" For how could that be a true vine which was expected to bring forth grapes and brought forth thorns?