When you believed, you were marked in him with a seal, the promised Holy Spirit, who is a deposit guaranteeing our inheritance until the redemption of those who are God’s possession.  (Ephesians 1:14)

To those ‘sealed’ as God’s possession, based on gospel faith, there is a deposit that acts as a guarantee of inheritance within His kingdom.  The word ‘deposit’ translates the Greek noun ἀρραβών (arrabón) meaning a down payment or surety; the first instalment of a payment to be redeemed in full at a later date.

Directly before his ascension, Jesus tells his disciples he would fulfil his promise:

‘And behold, I am sending the promise of my Father upon you. But stay in the city until you are clothed with power from on high.’  (Luke 24:49)

Specifically…

… the promise of the Father, which, he said, ‘you heard from me; for John baptized with water, but you will be baptized with the Holy Spirit not many days from now.’  (Acts 1:4b-5)

And ten days later, at the feast of Pentecost, Jesus makes good that promise to the eleven of the twelve disciples, who

… were all filled with the Holy Spirit and began to speak in other tongues as the Spirit gave them utterance.(Acts 2:4)

The promise then is not down payment, the Pentecostal visit is that, but if the indwelling Spirit is not itself the full payment, what is?  What is it the faithful will inherit in full?

Peter puts it this way:

According to (God’s) great mercy, he has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead,to an inheritance that is imperishable, undefiled, and unfading, kept in heaven for you,who by God’s power are being guarded through faith for a salvation ready to be revealed in the last time. (1 Peter 1:3-5)

From this it is seen that the faithful will only discover the full nature of the inheritance at a later date, at the very last, in fact.

In the meantime, the faithful must be content with the vicissitudes of mortal life, which may seem small – but only in retrospect:

So, we do not lose heart. Though our outer self is wasting away, our inner self is being renewed day by day. For this light momentary affliction is preparing for us an eternal weight of glory beyond all comparison, as we look not to the things that are seen but to the things that are unseen. For the things that are seen are transient, but the things that are unseen are eternal.  (2 Corinthians 4:16-18)

That glory awaits is revealed by Holy Spirit and he does bring comfort, the peace of God, as Jesus tells his disciples of…

… the Helper, the Holy Spirit, whom the Father will send in my name, he will teach you all things and bring to your remembrance all that I have said to you. Peace, I leave with you; my peace I give to you. Not as the world gives do I give to you. Let not your hearts be troubled, neither let them be afraid.  (John 14:26-27)

This is the down payment, peace, knowing that in turn, there is peace with God in eternity.  Now with the indwelling Spirit, after death dwelling with God.  John’s vision gives a foretaste, when he hears this declared:

‘Behold, the dwelling place of God is with man. He will dwell with them, and they will be his people, and God himself will be with them as their God. He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain any more, for the former things have passed away.’  (Revelation 21:3-4)

This is the inheritance that will be revealed to all in faith at the last day.