Westminster Shorter Catechism – Lord’s Day 20

Q & A 35
Q What is sanctification?
A Sanctification is the work of God’s free grace,*1 whereby we are renewed in the whole man after the image of God,*2 and are enabled more and more to die unto sin, and live unto righteousness.*3

*1 Ezekiel 36:27; Philippians 2:13; 2 Thessalonians 2:13.
*2 2 Corinthians 5:17; Ephesians 4:23-24; 1 Thessalonians 5:23.
*3 Ezekiel 36:25-27; Romans 6:4, 6, 12-14; 2 Corinthians 7:1; 1 Peter 2:24.