And you also were included in Christ when you heard the message of
truth, the gospel of your salvation. 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—to the
praise of his glory.
When you leave a deposit, you are
saying you will return to collect it one day.
The Holy Spirit enters the body of new believer and remains there until
the day that Spirit will be collected on the day of redemption—when Jesus
returns to earth and reboots the world.
It’s a promise that we will live in eternity forever. God wants us to know He's coming to get us.