Lev 20:7; [also read - I Peter 1:15-16] 7.Sanctify yourselves therefore, and be ye holy: for I am the Lord your God. 8.And ye shall keep my statutes, and do them: I am the Lord which sanctify you.
When we accepted Jesus Christ as our Lord and Savior we were sanctify unto God. Because of the blood of Jesus, believers are separated from this world and have become the sons of God (John 1:12). This is the initial sanctification wherein we were inducted into the Body of Christ, and no one can pluck us out of the hands of Jesus (John 10:28). Notwithstanding, sanctification is also a life long process, still. It means to be separated; therefore, we proclaim and declare the work done on the inside by separating ourselves from doing the sinful things we once did before coming to Christ. Making a noticeable change in our lifestyle, the way we talk, who we hang with, and most of all, having a reverential fear for God.
Some tend to live by the old cliché, “Once saved, always saved.” So there is no change in their lifestyle, they use cursing and foul language towards their fellow man, hang around with the wrong crowd, and there appears to be no fear of God in them. Are we looking at the Word of God as our guideline as to how we should live before God? Of course change takes time. But there are some changes that should have been immediately obvious. Once saved always saved? Were we ever saved at all? For holiness is not an option, but a command. If we really love God, then we will question our motives to see if we are sanctifying ourselves. Grace cannot abound where sin is dominate (Rom. 6:1). Also read (II Cor. 6:14-17).