As I read this I couldn't help to think about our beliefs in/about Jesus. While there is certainly historical common ground when it comes to Jesus there is something fundamentally different about what we believe - mostly we don't pursue God, God finds us. There is fundamentally a difference between living to earn God's favor and living out God's favor.
A great witness to this comes in the book of Hebrews. Here we see how faith, a forward, outward looking faith that anticipates the work of God.
First, in Hebrews 10 we read about the work of the priests to sanctify (purify/cleanse) God's people. Of course for the priests this was first a work of earning the forgiveness of their own sins and then later for others. In Hebrews 10:11-14 we read about how Jesus has come and eliminated this need for serial purification because he has done what could not be accomplished through the law.And every priest stands day after day at his service, offering again and again the same sacrifices that can never take away sins. But when Christ had offered for all time a single sacrifice for sins, “he sat down at the right hand of God,” and since then has been waiting “until his enemies would be made a footstool for his feet.” For by a single offering he has perfected for all time those who are sanctified.
Hebrews then goes in Chapter 11 to discuss the "heroes of the faith", those who lived in prior generations yet demonstrated a faith that is completed through the work of Christ. I believe what is implied here is that even before the birth of Christ there were those who longed for what they new God intended for humanity yet was beyond their grasp. So Hebrews writes, "Now faith is the assurance of things hoped for, the conviction of things not seen. Indeed, by faith our ancestors received approval." (Heb 11:1-2)
Jesus completes the longing of those who have gone before; those who longed for God's presence and reconciliation with God but knew it was beyond their power to achieve. They were faithful to walk forward to what God called them to. Even though what had been promised made no sense (a child in old age, the sacrifice of an only son, delivery from Egypt, a virgin birth) they trusted and walked forward in faith.
Jesus completes what we cannot do on our own and did so for each of them. In Jesus we experience God's forgiveness, God's presence in our life and we become a new creation. Jesus does complete God's promises and begins the recreation of our world.
Why does it matter and why is it any different? It's because it's not our job to seek God. It's not our job to earn God's salvation. Being a follower of Jesus isn't about following Jesus hoping to find or experience him. Being a follower of Jesus is a transformed and restored relationship with God so that all we do is not out of obligation but instead in response to the love and joy we experience as God enters the world and our lives. It's knowing the truth that our greatest longing is already fulfilled and our greatest joy, hope, peace and love comes to us simply in a manger. Unexpected, unmerited, unwarranted and irrational, true.