1. They, who are once effectually called, and regenerated, having a new heart, and a new spirit created in them, are further sanctified, really and personally, through the virtue of Christ’s death and resurrection, by his Word and Spirit dwelling in them: the dominion of the whole body of sin is destroyed, and the several lusts thereof are more and more weakened and mortified; and they more and more quickened and strengthened in all saving graces, to the practice of true holiness, without which no man shall see the Lord.

2. This sanctification is throughout, in the whole man; yet imperfect in this life, there abiding still some remnants of corruption in every part; whence ariseth a continual and irreconcilable war, the flesh lusting against the Spirit, and the Spirit against the flesh.

3. In which war, although the remaining corruption, for a time, may much prevail; yet, through the continual supply of strength from the sanctifying Spirit of Christ, the regenerate part doth overcome; and so, the saints grow in grace, perfecting holiness in the fear of God.

For further study see:

1. WSC35: What is sanctification?
2. WSC 36: What are the benefits which in this life do accompany or flow from justification, adoption, and sanctification?
3. WLC 75: What is sanctification?
4. WLC 75: What is sanctification?
5. WLC 77: Wherein do justification and sanctification differ?
6. WLC 78: Whence arises the imperfection of sanctification in believers
7. WCF CHAPTER 13: Of Sanctification