The prophet Isaiah offers a word of hope and comfort to the generation to follow that will experience the destruction of Jerusalem and the Babylonian Exile: "Comfort, comfort my people, says your God." Why? In the aftermath of tragedy, where does the comfort come from? The Promise of God.
Isaiah was told to encourage them that their exile would mark the extent of God's wrath and that he would soon send forth those to prepare the way to return to Jerusalem and rebuild the Temple.
Matthew calls upon Isaiah's words 500 years after the Exiles took comfort from it to proclaim that John the Baptist had fulfilled the prophecy a second time when he prepared the way for the Messiah, offering a message of repentance prior to the beginning of Jesus' public ministry.
Lastly, in any generation, we live by faith just as our ancestors did, we too take comfort from our knowledge that God keeps his promises, that no matter how we feel about the present or the future, God is working in our world. Our calling is to remain faithful, here and now, knowing that like always God's word will stand.