2. We are required to watch not only unto but in prayer. Satan is never more busy with Christians than when he sees them on their knees. He well knows the power of prayer; and this makes him tremble.
"Satan trembles when he sees
The weakest saint upon his knees."
You should, therefore, with the most untiring vigilance, watch in prayer against all wandering thoughts and distraction of mind. You will often experience, on such occasions, a sudden and vivid impression upon your mind of something entirely foreign from what is before you. This is no doubt the temptation of Satan. If you are sufficiently upon your watch, you can banish it, without diverting your thoughts or feelings from the subject of your prayer, and proceed as though nothing had happened. But, if the adversary succeeds in keeping these wild imaginations in view, so that you cannot proceed without distraction, turn and beseech God to give you help against his wiles. You have the promise, that if you resist the devil he will flee from you. These remarks apply both to secret prayer and public worship.
3. We have need of special watchfulness when we have experienced any comfortable manifestations of God's presence. It is then that Satan tempts us to consider the conflict over, and relax our diligence. If we give way to him, we shall bring leanness upon our souls.
4. We have need of double watchfulness when gloom and despondency come over our souls; for then the adversary seeks to stir up all the perverse passions of the heart.
5. Watch, also, when you feel remarkably cheerful. Satan will then, if possible, persuade you to indulge in levity, to the wounding of your soul, and the dishonor of religion.
6. We have need of special watchfulness in prosperity, that we forget not God; and in adversity, that we murmur not at his dealings with us.
7. Set a watch over your tongue, especially in the presence of the unconverted. "The tongue is a fire, a world of iniquity." David says, "I will keep my mouth with a bridle, while the wicked is before me." I do not mean that you should ever engage in any sinful conversation in the presence of Christians. I know some professors of religion will indulge in senseless garrulity among themselves, and put on an air of seriousness and solemnity before those whom they regard as unconverted. This they pretend to do for the honor of Christ. But Christ says, "Out of the abundance of the heart the mouth speaketh." God hates lip service. However, in the company of sinners and formal professors we are peculiarly exposed to temptation, and have need therefore to set a double guard upon our lips. A single unguarded expression from a Christian may do great injury to an unconverted soul.
8. Watch over your heart when engaged in doing good to others. It is then that Satan seeks to stir up pride and vain-glory.