Numbers 15:38

38Speak unto the children of Israel. A little farther on I will explain the object of this precept more fully: although it is plain from the next verse that God had no other object but to exercise the Jews in constant meditation upon the Law. For there was no religion contained in the fringes themselves, nor had that material texture any value in itself; but since men are lazy and forgetful in the cultivation of piety, God would by this aid make a provision for their infirmity. For when He says that they should “look upon it and remember,” He hints that they have need of these coarse rudiments, which may strike even their outward senses; and again, that, unless their memory was kept awake, nothing was more likely than that forgetfulness should steal upon them. But he presently adds, that God has no satisfaction in mere empty knowledge, but that He demands serious affections and practical performance. In the latter part of the verse he points out another requirement, viz., not only that their sluggishness should be stimulated, but also their wantonness restrained; for when he says “that ye seek not after your own heart,” he intimates that, unless God should restrain their wandering senses, they would be too much inclined to all kinds of superstitions and errors. And, first of all, by contrasting “the hearts and eyes” of men with His Law, he shews that He would have His people contented with that one rule which He prescribes, without the admixture of any of their own imaginations; and again, He denounces the vanity of whatever men invent for themselves, and however pleasing any human scheme may appear to them, He still repudiates and condemns it. And this is still more clearly expressed in the last word, when he says that men “go a whoring” whenever they are governed by their own counsels. This declaration is deserving of our especial observation, for whilst they have much self-satisfaction who worship God according to their own will, and whilst they account their zeal to be very good and very right, they do nothing else but pollute themselves by spiritual adultery. For what by the world is considered to be the holiest devotion, God with his own mouth pronounces to be fornication. By the word “eyes” he unquestionably means man’s power of discernment.