II. In the carrying on of this work we are to endeavour, to our utmost, to fence against the prevailing power of sin, by all those methods which are prescribed in the gospel, that so it may not have dominion over us; this is generally styled the work of mortification. The apostle speaks of _our old man being crucified with Christ, and the body of sin destroyed, that henceforth we should not serve sin_, Rom. vi. 6. and of our crucifying the flesh with the affections and lusts, and of our _mortifying the deeds of the body through the Spirit_, Gal. v. 24. that is, by his assistance and grace, which is necessary in order thereunto, Rom. viii. 13. This is a very difficult work, especially considering the prevalency of corruption, and the multitude of temptations that we are exposed to; the subtilty and watchfulness of Satan, who walks about like a roaring lion, seeking whom he may devour; the treachery of our own hearts, that are so prone to depart from God; the fickleness and instability of our resolutions; the irregularity of our affections, and the constant efforts made by corrupt nature, to gain the ascendant over them, and turn them aside from God: this it does sometimes by presenting things in a false view, calling evil good, and good evil; representing some things as harmless and not displeasing to God, that are most pernicious and offensive, endeavouring to lead us into mistakes, as to the matter of sin or duty, and to persuade us, that those things will issue well which are like to prove bitterness in the end; and attempting to impose upon us, as though we were in a right and safe way, when, at the same time, we are walking contrary to God, and corrupt nature is gaining strength thereby. But this will be farther considered, when we speak concerning the imperfection of sanctification in believers[69]. Now this renders it necessary for us to make use of those methods which God has prescribed for the mortification of sin; and in order thereunto, 1. We must endeavour to maintain a constant sense of the heinous nature of sin, as it is contrary to the holiness of God, a stain that cannot be washed away, but by the blood of Jesus, the highest instance of ingratitude for all the benefits which we have received, a bitter and an only evil, the abominable thing that God hates; it is not only to be considered as condemning, but defiling, that hereby we may maintain a constant abhorrence of it; and that not only of those sins that expose us to scorn and reproach in the eye of the world, but every thing that is in itself sinful, as contrary to the law of God.