2 Thessalonians 2:13
But we should always give thanks to God for you, brethren beloved by the Lord, because God has chosen you from the beginning for salvation through sanctification by the Spirit and faith in the truth.
Growing up in a typical African village full of idol worship, there are vessels that were said to be sanctified for use by the gods. These vessels are never used for any other thing other than what they had been sanctified for. Usage of such vessels for other things defiled them making them unfit to be used again.
Sanctification in its literal meaning is being set apart. That is, being set apart for use by God. Right from time, God chose men to carry out specific assignments for him. He chose Gideon, Moses, Elijah, Paul, etc… He even told Jeremiah before he was born he knew him and had chosen him (Jeremiah 1:5).
For us in Christ he told us we did not choose him but he chose us (John 15:16). Meaning, you had been set apart for his work even before you were born. Understanding this great privileged of being chosen by God almighty should ignite a desire to live a Holy life. Remember, even though you have been chosen it is your responsibility to accept to work in his call, It is your responsibility to remain sanctified.
God has called us into a life of Holiness, into walking in the Spirit, into understanding and functioning in the realm of the spirit. The bible says walk in the spirit and you wont fulfill the desires of the flesh (Galatians 5:16). If you find yourself fulfilling the desires of the flesh, be rest assured your garment is being stained, you become like the vessel that cannot be used for its original purpose. You become vulnerable, exposing yourself to be used by the devil.
I remember a story my mom told me, this story made me cry so much that i had to give my life to Jesus Christ. The story pictured how God had made me for fellowship with him, how he had set me apart to give him glory, but i rejected the offer of my maker and decided to please another. I cried so had because, i remembered how bad i felt when the big boys would always collect my football, play among themselves and stop me from playing. I pictured Jesus feeling so bad as i did the will of the devil instead of what he had made me to do.
Today, understand that as long as you have given your life to Christ, you have been set apart for his good will. If you find yourself fulfilling the desires of the flesh, run back to Jesus in confession. We must be determined to remain sanctified, we must give up all of us and be totally sold out for God for he aspects our devotion. God wants to trust you, determine to remain sanctified.