Ephesians 1:14

The Spirit is the guarantee (the first installment, the pledge, a foretaste) of our inheritance until the redemption of God’s own (purchased) possession (His believers), to the praise of His glory.

The Spirit provides the guarantee of our inheritance.   The blood of Jesus bought our salvation, and we bare the mark through the Holy Spirit living inside. The Spirit is our connection to God and our first taste of what our relationship to God will be in heaven.