I know two songs that go with this, so I'm going to post both. And only one is from Handel's Messiah.
"And the Glory of the Lord"
I like that the first verse assures comfort and then leads in to why we should find comfort: because we were promised a Savior. He would wash away our sins if we choose to repent. He would bring about our resurrection. He would be the means to our exaltation if we live righteously. And the promise of him coming and making those things possible has happened. We have every reason to rejoice and celebrate the baby born in Bethlehem who became the man at Gethsemane, on Calvary, and in the realms of glory.
The rest of the scripture speaks of his ability to do great things. I think the last verse refers to a future time, for there are still many today who do not know or believe in our Savior. But one day, they will not be able to deny who He is and all He has done for us. I look forward to that day--it will be nice not to have to disagree on the most vital part of who I am.