His divine power has granted to us all things that pertain to life and godliness, through the knowledge of him who called us to his own glory and excellence, by which he has granted to us his precious and very great promises, so that through them you may become partakers of the divine nature, having escaped from the corruption that is in the world because of sinful desire.
2 Peter 1:3-4
The truth of “Christ in you” is the theological fact God has most used to bring freedom, peace, joy, rest, grace, strength, etc., in my walk with him. Without the knowledge and experience of Christ’s personal presence, I would have quit the ministry, given up on the church, and forsaken all hope for victory over sin. The Spirit of Christ makes Christ’s hope available when I feel downcast, he assists my feeble attempts at ministry, and he is my constant knowledge of God’s love. Faith is the channel by which his his presence is made known and the avenue by which his life is manifest. Christ in you and me is our righteousness (acceptance before God), sanctification (Christian growth), and redemption (blood-bought freedom from slavery) (1 Cor. 1:30).
To be in Christ–that is redemption; but for Christ to be in you–that is sanctification! To be in Christ–that makes you fit for heaven; but for Christ to be in you –that makes you fit for earth! To be in Christ –that changes yours destination; but for Christ to be in you–that changes your destiny! The one makes heaven your home–the other makes this world His workshop.
Major Ian Thomas, The Saving Life of Christ/The Mystery of Godliness(Grand Rapids, MI: Zondervan, 1988), 22.