Luke 11:12

Consider then this, if the bread be not indeed the food of the soul in knowledge, without which it can not be saved, as, for example, the well planned rule of a just life. But the fish is the love of instruction, as to know the constitution of the world, and the effects of the elements, and whatever else besides wisdom treats of. Therefore God does not in the place of bread offer a stone, which the devil wished Christ to eat, nor in the place of a fish does He give a serpent, which the Ethiopians eat who are unworthy to eat fishes. Nor generally in the place of what is nourishing does he give what is not eatable and injurious, which relates to the scorpion and egg.

(de Quæst. Ev. lib. ii. qu. 22.) Or by the bread is meant charity, because we have a greater desire of it, and it is so necessary, that without it all other things are nothing, as the table without bread is mean. Opposed to which is hardness of heart, which he compared to a stone. But by the fish is signified the belief in invisible things, either from the waters of baptism, or because it is taken out of invisible places which the eye cannot reach. Because also faith, though tossed about by the waves of this world, is not destroyed, it is rightly compared to a fish, in opposition to which he has placed the serpent on account of the poison of deceit, which by evil persuasion had its first seed in the first man. Or, by the egg is understood hope. For the egg is the young not yet formed, but hoped for through cherishing, opposed to which he has placed the scorpion, whose poisoned sting is to be dreaded behind; as the contrary to hope is to look back, since the hope of the future reaches forward to those things which are before. (Serm. 105.) What great things the world speaks to thee, and roars them behind thy back to make thee look behind! O unclean world, why clamourest thou! Why attempt to turn him away! Thou wouldest detain him when thou art perishing, what wouldest thou if thou wert abiding for ever? Whom wouldest thou not deceive with sweetness, when bitter thou canst infuse false food?

In these words our Saviour gives us a very necessary piece of instruction. For often-times we rashly, from the impulse of pleasure, give way to hurtful desires. When we ask any such thing from God, we shall not obtain it. To show this, He brings an obvious example from those things which are before our eyes, in our daily experience. For when thy son asks of thee bread, thou givest it him gladly, because he seeks a wholesome food. But when from want of understanding he asks for a stone to eat, thou givest it him not, but rather hinderest him from satisfying his hurtful desire. So that the sense may be, But which of you asking his father for bread, (which the father gives,) will he give him a stone? (that is, if he asked it.) There is the same argument also in the serpent and the fish; of which he adds, Or if he asks a fish, will he for a fish give him a serpent? And in like manner in the egg and scorpion, of which he adds, Or if he ask an egg, will he offer him a scorpion?