_Direct._ XII. Cast out vain and sinful thoughts in the beginning, before they settle themselves and make a dwelling of thy heart. They are easiliest and safeliest resisted in the entrance. Thy heart will give them rooting and grow familiar with them, if they make any stay. Besides, it shows the greater sin, because there is the less resistance, and the more consent. If the will were against them, it would not let them alone so long. Yea, and their continuance tendeth to your ruin; it is like the continuance of poison in your bowels, or fire in your thatch, or a spy in an army: as long as they stay they are working toward your greater mischief. If these flies stay long they will blow and multiply; they will make their nests, and breed their young, and you will quickly have a swarm of sins.
_Direct._ XIII. Take heed lest any practical error corrupt your understandings; or lest you be engaged in any ill design: for these will command your thoughts into a course of sinful attendance and service to their ends. He that erreth and thinks his sin is his virtue or his duty, will indulge the thoughts of it without control; yea, he will drive on his mind to such cogitations; and steal from the authority and word of God, the motives and incentives of his sin. As false prophets speak against God in the name of God, and against his word as by the pretended authority of his word; so an erring mind will fetch its arguments from God and from the Scripture, for those sinful thoughts which are against God and Scripture. And if evil thoughts will so hardly be kept out when we plead the authority of God and his word against them, and do the best we can to hinder them; how will they prevail when you plead the authority of God and the sacred Scriptures for them, and take it to be your duty to kindle and promote them! For instance; all the sinful thoughts by which the Romish clergy are contriving the support of their kingdom of darkness in the world, and the continuance of their tyranny in the church, are but the products of their error, which tells them that all this should be done, as pleasing to God, and profitable to the church. All the bloody thoughts of persecutors, against the church and holy ways of Christ, have been cherished by this erroneous thought. John xvi. 23, "The time cometh that whoever killeth you, will think that he doth God service; and these things they will do unto you, because they have not known the Father nor me." All Paul's bloody contrivances and practices against the church did come from this. Acts xxvi. 9, "I verily thought with myself, that I ought to do many things contrary to the name of Jesus of Nazareth: which thing I also did." All the scornful and reproachful thoughts and speeches of many of the ungodly against a holy life, are hence: 1 Pet. iv. 4, "They think it strange that you run not with them to excess of riot, speaking evil of you." The vain babbling of hypocrites, who cheat their souls with idle lip-labour, instead of the spiritual service from the heart, and the sacrifice of fools, who offer God some outward thing, while they deny him their hearts and holy obedience, do proceed from this, that "they think to be heard for their much babbling," Matt. vi. 7, "and they consider not that they do evil," Eccl. v. 1. All the self-flattery and presumption of the ungodly, and consequently all their ungodly lives, are much from their erroneous thoughts: "He that thinketh he is something when he is nothing, deceiveth himself," Gal. vi. 3. O come into the light, and forsake your darkness! for sinful thoughts are like hobgoblins and hags, that fly from the light; and like worms and serpents, that creep into holes, and crawl and gender in the dark.
_Direct._ XIV. Remember what an opening of thoughts there will be, when you come into the light, either here by conviction, or at the furthest at the day of judgment. Then you will be ashamed to see what filth and vanity you entertained; and with what dross and rubbish you stuffed your minds. When the light comes in, what abundance of things will you see to your astonishment, in the dungeon of your hearts, which now you take no notice of! Remember, that all your hidden thoughts must one day be brought into the open light. Say not that this is a thing impossible, because they are so numerous: for God who seeth them all at once, and causeth his sun to illuminate so many millions at once, can make you see them all at once, and yet distinctly, and see the shame and filthiness of every one of them.