Westminster Larger Catechism
Q. 75. What is sanctification?
A. Sanctification is a work of God’s grace, whereby they whom God hath, before the foundation of the world, chosen to be holy, are in time, through the powerful operation of his Spirit[314] applying the death and resurrection of Christ unto them,[315] renewed in their whole man after the image of God;[316] having the seeds of repentance unto life, and all other saving graces, put into their hearts,[317] and those graces so stirred up, increased, and strengthened,[318] as that they more and more die unto sin, and rise unto newness of life.[319]
Westminster Shorter Catechism
Q. 35. What is sanctification?
A. Sanctification is the work of God’s free grace,[97] whereby we are renewed in the whole man after the image of God,[98] and are enabled more and more to die unto sin, and live unto righteousness.[99]
Daily Westminster 