"And you also were included in Christ when you heard the word of truth, the gospel of your salvation. Having 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: 13 & 14
When I seal an envelope, I am keeping it safe and secure until it is delivered to the addressee. This is what God has done for me, ever since I said "I believe in Jesus as my Lord and Savior. I confess I am a sinner for whom Jesus gave his life." While I wait to see him face to face, he keeps me secure with his Holy Spirit as a deposit. Praise God I am his precious possession!