"Now He that hath wrought us for the selfsame thing is God, who also hath given unto us the earnest of the Spirit" (II Corinthians 5:5).
This is a fascinating concept and a wonderful reality. The indwelling presence of the Holy Spirit in the life of the believer is said to be an "earnest" -- that is, a pledge or deposit -- on an ultimate fulfillment of a magnificent promise from God Himself. The word translated "earnest" (Greek, arrhabon) is essentially a transliteration of its Hebrew equivalent (arabown), translated "pledge" in the Old Testament (see Genesis 38:17-20).
Now if the guiding presence of God, through the Holy Spirit, is merely an earnest payment, the fulfillment must be glorious beyond comprehension. This "selfsame thing," as our text calls it, is a wonderful "house which is from heaven," the spiritual body we shall receive when we go to be with the Lord (II Corinthians 5:1-2).
The phrase also occurs in II Corinthians 1:22: "Who hath also sealed us, and given the earnest of the Spirit in our hearts." In context, the earnest payment here is associated with the "sealing" of God and the assurance that "all the promises of God in Him are yea, and in Him Amen" (v.20).
The third and last use of this word in the New Testament is in Ephesians 1:13-14: "In whom also after that ye believed, ye were sealed with that holy Spirit of promise, Which is the earnest of our inheritance until the redemption of the purchased possession." We are "joint-heirs with Christ" (Romans 8:17), and He is to inherit all things.
Thus, the Holy Spirit, a present possession of all who have received Christ as Savior, is also God's pledge of a glorious future -- a perfect body, a great inheritance, and the certain fulfillment of all of God's gracious promises. HMM