When writing to the church in Corinth, Paul referred to them as those who had been sanctified, perhaps to remind them of how they were falling short of their calling.  

1 Corinthians 1:2 (ESV)
² To the church of God that is in Corinth, to those sanctified in Christ Jesus, called to be saints together with all those who in every place call upon the name of our Lord Jesus Christ, both their Lord and ours:

The word sanctified means “to make holy.”   It refers to the state of purification one enters when they obey the gospel of Christ.

We must recognize that there are two types of sanctification: one that God performs in us and the other that we accomplish ourselves.  These two kinds of sanctification have been referred to as positional and progressive sanctification.

When we obeyed the gospel, we were moved positionally from outside of Christ to inside of Christ (Galatians 3:27).  We were moved from the darkness of this world into God’s marvelous light (Colossians 1:13), and it all happened by the sanctifying power of the Holy Spirit (1 Peter 1:2).

We owe our positional sanctification to God.  We cannot sanctify ourselves positionally.  We cannot wash away our own sins.  Only God, by the blood of His Son and our Savior, Jesus Christ, can do that.  This is why the Bible says that we are saved by grace.  God, by His unmerited favor, sacrificed His only begotten Son so that we might be sanctified.  He did what the law could not do by sending His Son to condemn sin in the flesh (Romans 8:3).

If you are a Christian, be thankful every day that you have been sanctified by God.  When you lie your head down tonight, be mindful that the sweet fellowship that you have with God is only possible because Jesus was willing to give up the riches of heaven and be made poor, just so we, by His poverty, might be rich (2 Corinthians 8:9).

Does this mean we have no responsibility when it comes to sanctification?  No, it is up to us to maintain it.  This is what progressive sanctification is.  It is the willful determination to live a separated, set-apart life, devoted to God.

2 Corinthians 7:1 (ESV)
¹ Since we have these promises, beloved, let us cleanse ourselves from every defilement of body and spirit, bringing holiness to completion in the fear of God.

The word holiness is from the same family of words as sanctification.  We perfect holiness by living sanctified lives.  And there is something else for us to remember —living sanctified lives is not something we do part-time.  If we are the kind of obedient children that God wants us to be, then we are habitually holy.

Every day we demonstrate our sanctification.  Everywhere we go, we demonstrate that we are set apart.  Everything we do, we do it with holiness.  Peter said that we are to be holy in all of our conduct (1 Peter 1:15).

People around us may cuss and curse, but we do not because we are set apart.  They may dance, drink, and do drugs, but we do not because we are holy.  People around us break the law and bend the rules, but we do not because we have been set apart, and now we are living sanctified lives.  As Christians, it does not matter what is going on in this sinful world; we have been separated, set apart, and sanctified, and if we are faithful to God, it is seen by our daily living.

As you wind down for the night, think about these things.