The scope of our Saviour in these verses is the very same as in the verses immediately preceding, viz. to correct the jejune interpretation which the Pharisees had put upon the Divine law, and to show that he, instead of coming to destroy the law, came to fulfil it, as other ways, so by giving a more strict and true interpretation of it; and whereas they interpreted it only as to overt acts, which disturb human society and break civil order, he showeth that it reacheth to the inward thoughts, and unlawful desires of the heart, and any means that have a tendency to such prohibited acts. It was said by God to those fathers of the Jews,
Thou shalt not commit adultery, Exo_20:14. This law (saith our Saviour) your doctors expound, You shall not carnally lie with a woman that is not your wife; but there is a great deal more in it than so, for he that but secretly in his heart desireth such a thing, or taketh pleasure in such thoughts, and casts his eyes upon a woman in order to such a thing, is in the sight of God an adulterer. Hence we read of eyes full of adultery, to avoid which Job made a covenant with his eyes, Job_31:1, and would not suffer his heart to walk after his eyes, Job_31:7. We must so interpret the commandments of God, as not to extend them only to forbid or command those acts which are plainly mentioned in them, but the inward pleasing of our hearts with such things as are forbidden, the desires of our hearts after them, or whatsoever is a probable means to give us that sinful pleasure of our thoughts, or further inflame such unlawful desires in our souls.