Mankind's will and motives stem solely from carnal origins. Selfish, sinful motives. At his best state he is altogether unrighteous. If it were up to mankind to sanctify themselves, it could not approach anything close to holiness. Therefore, holiness and sanctification must be God's divine gracious working toward us, and in us. God's holiness is made possible through God’s power. It is His will, His Word, and His work. Our part is in surrendering, yielding and obeying. Sanctification is not obtained through the will of man, but the will of God.
”For this is the will of God, even your sanctification, that ye should abstain from fornication: That every one of you should know how to possess his vessel in sanctification and honour;”-1 Thessalonians 4:3-4
It is God’s will that we might be sanctified. That we might be cleansed from all sin, and filled with His Holy Spirit. Sanctification will bring with it an instantaneous transformation. A profound change. A turning from darkness to light; from the power of satan to that of God. Since it is in the will of God, the work must be performed by God. This work is made possible because of Jesus Christ, and manifested by faith. He does not need anything more or less from us than belief. Believe and submit. Trust and obey.
“Now unto him that is able to keep you from falling, and to present you faultless before the presence of his glory with exceeding joy, To the only wise God our Saviour, be glory and majesty, dominion and power, both now and ever. Amen.”-Jude 1:24-25
Once we are sanctified, how are we to stay sanctified? How are we kept free from the purpose and practice of sin? By the power of God. The same power that spoke the universe into existence keeps you free from sin. The same power that formed the heaven and earth keeps you free from sin. The same power that raised Jesus from the grave, keeps you free from sin. It is not the will of man, or the power of man, but of God. If God has power enough to deliver you from the bondage of sin, does he not have power enough to keep you free from it as well? He can, and he will, because it is in His will. To live the sanctified life is to live a life walking in the will of God. A life surrendered to Christ. Kept by the power of God, directed by the indwelling of the Holy Spirit.