Luke 11:36

Now when He adds, If thy whole body therefore, &c. by the whole of our body He means all our works. If then thou hast done a good work with a good intention, having in thy conscience nothing approaching to a dark thought, though it chance that thy neighbour is injured by thy good actions, nevertheless for thy singleness of heart shalt thou be rewarded with grace here, and with glorious light hereafter; which he signifies, adding, And as the bright shining of a candle shall it give thee light. These words were especially directed against the hypocrisy of the Pharisees, who sought for signs that they might catch him.

That is, If thy material body, when the light of a candle shines upon it, is made full of light, so that not one of thy members is any longer in darkness; much more when thou sinnest not, shall thy whole spiritual body be so full of light, that its brightness may be compared to the shining of a candle, while the light which was in the body, and which used to be darkness, is directed whithersoever the understanding may command.

(Hom. 20. in Matt.) If then we have corrupted the understanding, which is able to let loose the passions, we have done violence to the whole soul, and suffer dreadful darkness, being blinded by the perversion of our understanding. Therefore adds he, Take heed, therefore, that the light which is in thee be not darkness. He speaks of a darkness which may be perceived, but which has its origin within itself, and which we every where carry about with us, the eye of the soul being put out. Concerning the power of this light He goes on to say, If thy whole body therefore be full of light, &c. &c.

(de Cons. Ev. lib. ii. c. 39.) Luke indeed relates this in the same place as Matthew, but in a somewhat different order. But who does not see that it is an idle question, in what order our Lord said those things, seeing that we ought to learn by the most precious authority of the Evangelist, that there is no falsehood. But not every man will repeat another's words in the same order in which they proceeded from his mouth, seeing that the order itself makes no difference with respect to the fact, whether it be so or not.

But as if the eye of the body be light the body will be light, but if dark the body will be dark also, so is it with the understanding in relation to the soul. Hence it follows, If thine eye be single, thy whole body will be full of light; but if evil, thy whole body will be full of darkness.