Sanctify: to make holy; set apart as sacred; consecrate; to purify or free from sin. Thus sanctification is the process by which we become holy – it is God’s transformation of a believer’s whole being, that is the mind, will, behaviours, and affections through the work of the Holy Spirit.
In Philippians 2 verse 12 we read, “Therefore, my beloved, as you have always obeyed, not as in my presence only, but now much more in my absence, work out your own salvation with fear and trembling;”, which we often translate to ourselves (or have interpreted for us) as being that we need to become sanctified by our own efforts, to make ourselves holy, pure, just and blameless. However, the scriptures of the New Testament consistently state that our sanctification is wholly a gift of God, not by what we do. It is merely our job to remember that we are wholly holy. 2 Thessalonians 2:13b says this expressly, “God from the beginning chose you for salvation through sanctification by the Spirit and belief in the truth”, so that even from the beginning, even from before the fall, even from before creation, you were eternally sanctified in the Godhead. There is nothing else to do, believe it!