God is a giving God, Who gives Himself in His promises. By faith, which corresponds to promise, humans receive the justice of God. This fact flows through the whole theology of Luther. It was, for Luther, one of the greatest discoveries that the justice of God is not a demand, but a gift. As a result of this he discovered the distinction between law and Gospel. The Gospel as a promise has to be separated sharply from the demands of the law, which just convicts of sin. The Gospel is the definitive Word of God. It is not an announcement of promises which is just fulfilled and actualized in the future, but primarily it is a legal promise with an immediate effect in the lives of believers.
The promise is an effective word of forgiveness, which became central to Luther’s sermonizing. This is reflected in four characteristics:
- In the vocative case from an I to a you;
- In speaking in the present tense;
- In proclamation that summarizes the promise;
- In the explicit or implicit authority of the speaking I.
The words spoken at baptism are thus understood as a promise. The promise does what baptism says: the token is not separated from the deed, but is the fulfilment of it. The words uttered at the Lord’s Supper present the risen Crucified as the real Person present. Luther has these words in his ear, eye and heart when he observes all the deeds of the triune God as giving promise and promising giving.