(37-40) If there be pestilence. — He then passes on to the various plagues threatened in the Law — famine, pestilence, blasting of the corn, mildew on the fruit, locust and caterpillar (see Leviticus 26:25-26; Deuteronomy 28:22-24; Deuteronomy 28:38-42), the distress of siege, so terribly depicted (Deuteronomy 28:52-57), and so often terribly fulfilled (not least in the last great siege of Jerusalem), and adds, to sum up all, “whatsoever plague, whatsoever sickness there be.” Through any, or all of these, he pictures each man as brought to “know the plague of his own heart” — that is, as startled into a consciousness of sin, and recognition of it as the true “plague,” the cause of all outward plagues, and so drawn to prayer of penitence and of godly fear.
Thou only, knowest the hearts... of men. The emphasis laid on this knowledge of the heart (as in Psalms 11:4; Psalms 139:2-4; Jeremiah 17:9-10) as the special attribute of Deity, though, of course, belonging to all vital religion, yet marks especially the leading thought of the Psalms and the Proverbs, which always realise the presence of God, not so much in the outer spheres of Nature and history, as in the soul of man itself. It carries with it, as here, the conviction that, under the general dealings of God’s righteousness with man, there lies an individuality of judgment, making them to each exactly what his spiritual condition needs. The plague, for example, which cuts off one man unrepentant in his sins, may be to another a merciful “deliverance out of the miseries of this sinful world.”