Singer Michael Card wrote a song called The Promise, and he wrote a little Christmas devotional on this theme:
Christianity is founded on a promise. Faith involves waiting on a promise. Our hope is based on a promise.
Promises are made with words. … .that part of myself that goes with every promise is given to you through my words….
Our God is the great maker of promises… His word, our Bible, is a collection of the promises… most of these concern Jesus, who came to be known as “the Promised One”
Through all these promises, God was trying to give something of Himself to Adam, and to Israel, and finally to us. The Bible tells us that when the Promised One came, the Lord poured all of Himself into Him.
What a costly thing it can be to make a promise – it cost Jesus His life.