"So long as we are clothed in this temporary dwelling we have a painful longing, not because we want just to get rid of these 'clothes' but because we want to know the full cover of the permanent house that will be ours. We want our transitory life to be absorbed into the life that is eternal. Now the power that has planned this experience for us is God, and he has given us his Spirit as a guarantee of its truth." 2 Corinthians 5:4,5
"HIS Spirit as a GUARANTEE." I don't know which of those two words to talk about first - they're both so preposterously wonderful!
God...has given you...His Spirit. His own personal inner life. He has just given Him to you. You may abide within, and rely upon, the same inner resources that commanded and upheld the earthly life of Jesus.
And He has been given to you "as a guarantee" - as, in the Greek, an ἀρραβῶνα: "a present; a pledge; as earnest-money." What He has put in you - His very own Spirit - is a downpayment on the day when you'll be swallowed up in His glory.
Your experience of, and your delight in the Holy Spirit today is the degree to which you're already in Heaven.
Shall we go live there?