Some decisions and transactions are so monumental they are not completed all at once.
The purchase of a million-dollar house, for example, is usually done in two or more stages. Often this real estate transaction begins with the payment of earnest money, a.k.a. the “down payment”. This action of good faith informs the seller that the buyer is serious and intent on completing this purchase soon.
The monumental decision of choosing and marrying a mate is typically not carried out in one day. In almost all cultures around the world, there is a betrothal period. In Jesus’ day, a betrothal was viewed as legally binding, even though the wedding day had not yet come. For a betrothal to be broken, a writing of divorce had to be given. (This background information sheds great light on Matthew 1:18-25.)
In procuring our redemption God made a down payment: “the Holy Spirit of promise…is the guarantee (or “earnest”—KJV) of our inheritance until the redemption of the purchased possession” (Ephesians 1:13-14).
The down payment of our redemption has been made; the rest of our redemption awaits us. It will be completed at the coming of the great and final day of the Lord.