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--to the praise of his glory. Ephesians 1:13-14
I remember the first house Lori and I bought. We signed what seemed like a mountain of paperwork and then wrote a really big check; the down payment. The down payment did not pay off the house. It was simply a promise that every month we would continue to pay what we owed.
In our passage today, Paul explains that the Holy Spirit is God's down payment to us. "Deposit guaranteeing," one Greek word is a legal term meaning "first installment." The word signifies the first payment, which serves as a pledge for the completion of the transaction. The Holy Spirit is the promise that the work God began in us will be carried on to completion (Philemon 1:6).
The gift of the Holy Spirit, given the moment we believe, is God's commitment to future blessings of eternal life and our great reward in heaven. It is the Spirit who testifies with our spirit that we are indeed children of God (Romans 8:16). It is by the "Spirit of sonship" that we can cry out "Abba, Father" (Romans 8:15).
Father, thank You for the Holy Spirit that lives within us. Thank You for the assurance that the work You start will be finished. In Jesus' name. Amen.