The section of our history on which we are now entering is an extensive one, embracing many important principles of Christian experience and divine dealing. The facts of the case are, doubtless, familiar to the reader; but it will be profitable to look closely at them. David's sin led to Absalom's conspiracy. "And it came to pass, after the year was expired, at the time when kings go forth to battle, that David sent Joab, and his servants with him, and all Israel; and they destroyed the children of Ammon, and besieged Rabbah. _But David tarried still at Jerusalem_" (2 Sam. xi. 1). David, instead of being out at the head of his army, exercising himself in the hardships and fatigues of war, was quietly reposing at home. This was giving the enemy a manifest advantage over him. The moment a man absents himself from his post of duty, or retires from the place of conflict, he renders himself weak. He has taken off the harness, and will, undoubtedly, be pierced by the arrow of the enemy. While at work for the Lord, be the work what it may, nature is kept under pressure; but when at ease, nature begins to work, and feel the action and influence of external things. We should seriously ponder this. Satan will ever find mischief for idle hearts, as well as idle hands. David was made to feel this. Had he been at Rabbah with his army, his eye would not have rested upon an object calculated to act upon the corrupt principle within; but the very act of tarrying at home afforded an opening for the enemy to come in upon him. It is well to be ever on the watch, for we have a watchful enemy. "Be sober, be vigilant," says the apostle; "because your adversary, the devil, as a roaring lion, walketh about, seeking whom he may devour." Satan watches his opportunity, and when he finds a soul unoccupied with his proper service, he will surely seek to involve him in evil. It is, therefore, safe and healthful to be diligently engaged in service--service flowing out of communion with God, for we are thus in an attitude of positive hostility to the enemy; but if we are not acting in hostility, he will use us as instruments for his own ends. When David failed in energy as the captain of the hosts of Israel, he became the slave of lust. Sad picture! Solemn, most solemn warning for our souls! The believer is the subject either of the energy of the Spirit, or the energy of the flesh; if he fails in the former, the latter will most assuredly predominate, and then he becomes an easy prey to the enemy. Thus it was with David. "At the time when kings go forth to battle" he was at rest in his house, and Satan presented a bait which proved too much for his poor heart. He fell--grievously, shamefully fell! Nor was his fall now a mere mistake. No; he fell into a deep pit of moral evil, of vile corruption, and his fall utters the solemn admonition, "_Keep under the body_." Nature must be judged, or we shall make shipwreck.