23 May the God of peace himself sanctify you entirely; and may your spirit and soul and body be kept sound and blameless at the coming of our Lord Jesus Christ. 24 The one who calls you is faithful, and he will do this. (1 Thess. 5:23-24, NRSV)
The work God has started in you will be complete. He alone is the One who sanctifies you entirely.
And he is able.
We serve the One who is faithful.