To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory. (Colossians 1:27)
What assurance does the believer have that his salvation will not be lost? that he will reach the ultimate goal of heaven?
On the night before He was crucified our Lord made the remarkable statement of John 14:20, "At that day ye shall know that I am in my Father, and ye in me and I in you." Of the twenty words in our English translation nineteen words are of one syllable, and the twentieth is a two-syllable word that is usually one of the first words learned by any child. Our Lord wanted everyone to understand clearly. Three reasons are given for the security of the believer: the fact that Christ is in the Father, that the believer is in Christ, and that Christ is in the believer. Any one reason would be sufficient. The last, however, was the Lord's assurance to the disciples that His indwelling presence would be with them after His death and resurrection. Jesus Christ would not only be for them and with them, but He would also spiritually indwell them.
"Ours is not a dead Savior. He is a living Savior. He arose from the grave, and ascended to the Father's right hand. There He is our Intercessor and Advocate. But He also dwells within the believer--He lives in our hearts by His Holy Spirit, whose temples we are (1 Cor. 6:19). This is the Christian life--the life of Christ Himself in the heart. The great revelation of which Paul was minister to make known to all who believe, is this: 'Christianity is Christ--Christ in you, the hope of glory' "
(E. Schuyler English).
This is not only doctrine to be known but also a life to be lived. He not only wants to indwell us but also to be Lord of our lives, to be enthroned in our hearts.
(this devotional by Dr. Elliot R. Cole)