Psalms 39:3

3. My heart became hot within me He now illustrates the greatness of his grief by the introduction of a simile, telling us that his sorrow, being internally suppressed, became so much the more inflamed, until the ardent passion of his soul continued to increase in strength. From this we may learn the very profitable lesson, that the more strenuously any one sets himself to obey God, and employs all his endeavors to attain the exercise of patience, the more vigorously is he assailed by temptation: for Satan, whilst he is not so troublesome to the indifferent and careless, and seldom looks near them, displays all his forces in hostile array against that individual. If, therefore, at any time we feel ardent emotions struggling and raising a commotion in our breasts, we should call to remembrance this conflict of David, that our courage may not fail us, or at least that our infirmity may not drive us headlong to despair. The dry and hot exhalations which the sun causes to arise in summer, if nothing occurred in the atmosphere to obstruct their progress, would ascend into the air without commotion; but when intervening clouds prevent their free ascent, a conflict arises, from which the thunders are produced. It is similar with respect to the godly who desire to lift up their hearts to God. If they would resign themselves to the vain imaginations which arise in their minds, they might enjoy a sort of unrestrained liberty to indulge in every fancy; but because they endeavor to resist their influence, and seek to devote themselves to God, obstructions which arise from the opposition of the flesh begin to trouble them. Whenever, therefore, the flesh shall put forth its efforts, and shall kindle up a fire in our hearts, let us know that we are exercised with the same kind of temptation which occasioned so much pain and trouble to David. In the end of the verse he acknowledges that the severity of the affliction with which he was visited had at length overcome him, and that he allowed foolish and unadvised words to pass from his lips. In his own person he sets before us a mirror of human infirmity, that, being warned by the danger to which we are exposed, we may learn betimes to seek protection under the shadow of God’s wings. When he says that he spake with his tongue, it is not a superfluous mode of expression, but a true and fuller confession of his sin, in that he had not only given way to sinful murmuring, but had even uttered loud complaints.