“Those who are united to Christ, effectually called, and regenerated, have a new heart and a new spirit created in them; and by His Word and Spirit dwelling within them, this personal work of sanctification is indeed carried further. All these blessings accrue to them by reason of the merits of Christ’s death and resurrection. Sin’s mastery over them is completely broken; the evil desires to which it gives birth are increasingly weakened and dealt their death-blow; and saving graces in them are increasingly enlivened and strengthened. The practice of all true holiness, without which no man shall see the Lord, is thus promoted.
“Sanctification, as defined in this way, extends to every part of man, yet remains incomplete in this life. Sin’s corrupt remnants continue to defile all parts of man, causing within him a continual warfare that does not admit of reconciliation; the flesh rises up against the Spirit and the Spirit against the flesh.
“In the war of flesh versus Spirit, sin’s corrupt remnants may for a time gain the upper hand, yet the continual supply of strength from the sanctifying Spirit of Christ enables man as a new creature to gain the victory. And so the saints grow in grace, moving on towards a fullness of holiness in the fear of God. They earnestly endeavor to live according to heaven’s laws, and to render gospel obedience to all the commands which Christ, as their head and king, has laid down for them in His Word.”
(The Baptist Confession of Faith of 1689, Chapter 13 – Sanctification, Articles I-III; ©1975, Carey Publications, Ltd., 75 Woodhill Road, Leeds, U.K., LS16 7BZ; http://www.founders.org/library/bcf/bcf-13.html)