When you believe in Him, that is, in Jesus Christ you are “sealed with the promised Holy Spirit, who is the guarantee of [your] inheritance until [you] acquire possession of it, to the praise of His glory.” (Ephesians 1:13-14)
What you will acquire eventually is your inheritance. What you acquire now, in conjunction with your belief in Jesus Christ, is God the Holy Spirit. He is your seal, similar to a stamp of ownership in that you are purchased by the blood of Christ crucified. His blood buys you for God the Father, and His Holy Spirit guarantees your acceptance into the family of God.
Your inheritance is one you share with Israel. Israel is predestined to be the nation of God. You also – because you “hear the Word of Truth, the gospel of your salvation” and believe – are a child of God.
Therefore, “having the eyes of your heart enlightened… [you] know what is the hope to which He calls you, what are the riches of His glorious inheritance in the saints, and what is the immeasurable greatness of His power toward us who believe.” (Ephesians 1:18-19)
You are called to hope, to a rich inheritance through Christ’s great power to save. And, you are sealed with God, the promised Holy Spirit.