is,
Being made holy.
(The act of God's grace by which men are purified from sin and the world, and exalted to a supreme love to God.)

Also, the act of separating and setting apart for the service and worship 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; Not in the lust of concupiscence, even as the Gentiles which know not God...
1 Thessalonians 4:3-5