Origen's Commentary on the Gospel of Matthew

But I wonder if the disciples thought, before the saying was explained to them by Jesus, that their Teacher and Lord was forbidding them to beware of the sensible leaven of the Pharisees or the Sadducees as impure, and on this account forbidden, lest they might use that leaven because they had not taken loaves. And we might make a like inquiry in regard to other things; but by-way of illustration the narrative about the woman of Samaria sufficeth, “Every one that drinketh of this water shall thirst again; but whosoever drinketh of the water that I shall give him shall never thirst.” For there, also, so far as the mere form of expression is concerned, the Samaritan woman would seem to have thought that the Saviour was giving a promise about sensible water, when He said, “Whosoever drinketh of the water that I shall give him shall never thirst.” And those things then must be figuratively interpreted, and we must examine and compare the water of the spring of Jacob from which the woman of Samaria drew water with the water of Jesus; and here the like must be done; for perhaps the loaves were not baked, but a kind of raw leaven solely, the teaching, namely, of the Pharisees and Sadducees.