17 Sanctify them through thy truth: thy word is truth.
18 As thou hast sent me into the world, even so have I also sent them into the world.
When you give your heart to God, you have to learn to live a sanctified life. That means removing sin and living pure before God. You do this by praying and reading the word of truth. You will find perfect instructions on how to live sanctified. So get in the word and be sanctified by the word of God.