The first reading tells how King David, after establishing his throne, and building his palace, set his mind on building a fitting temple for the Lord. The Prophet Nathan, on being told of the king’s intent, told him that God would be pleased with any temple David would build.
However, that night God let Nathan know that he did not want or need David to build him a temple. (He was reserving that task for David’s son, Solomon.)
But God, not wanting David to feel pushed aside, made a great promises to him. He said the following.
“Your house and your kingdom shall endure forever before me, your throne shall stand firm forever.”
Over the following centuries the people of Jerusalem came to feel that no matter how badly they behaved, God would always keep his promise to keep their temple from falling. In Jeremiah’s time, three centuries later, the people had given up praying in the temple. They had come to see their temple as a good luck charm. In passing it, they always knocked on the wall, repeating the words, “The temple of the Lord. The temple of the Lord. The temple of the Lord!”
Toward the end of Jeremiah’s time, the Babylonian army invaded Jerusalem, reducing the temple to gravel. The people then complained against God, saying he had failed in the promise he made when he said, “Your house and your kingdom would endure forever.”
Why bring this matter up now? Well, this is the night when God would come through on his promise. Tonight he is sending us a child king whose house and kingdom will endure forever.”