When my brothers and I were growing up, and wrapped gifts began appearing under the tree in the days leading up to Christmas, we couldn't keep our hands off the gifts. Our mom would tell us to leave them alone, and we would do the best we could. But they were SO enticing! Mom even reached the point where she wouldn't put our names on the packages to prevent us knowing which gift belonged to whom. When we finally got to open the gifts, our anticipation turned into joy as we removed the outer paper to reveal the gift inside.
As we all know, the true gift of Christmas is the life, death, and resurrection of Jesus Christ which resulted in reconciliation for all of humankind with the God of the universe! Jeremiah is writing at a time when the promise of the Messiah is yet to be fulfilled, the gift to be unwrapped. The Hebrews know the Messiah will come, but they don't know exactly how the fulfillment will happen. There's a mystery, an anticipation, and an expectancy of what is to come.
While the presence of God was given to a few individuals in the time before Jesus came, for most Hebrews God's presence was manifested in the physical Temple, not in the hearts of individual believers. Jeremiah and his people had to work harder to follow God through the established rituals and animal sacrifices. However, they knew deep down the rituals and sacrifices weren't enough.
Jeremiah encourages the people when he says, "No longer shall they teach one another, or say to each other, 'Know the LORD,' for they shall all know me, from the least of them to the greatest, says the LORD; for I will forgive their iniquity, and remember their sin no more" (v. 34). This fulfillment came with Jesus's birth, death, resurrection, and coming of the Holy Spirit. This New Covenant means we don't have to be reminded to know the Lord. We know him because he lives within us, and he will never leave us. The revealing of Jeremiah's prophetic expectation is the gift and joy we celebrate at Christmas!