The power of God at work in the person of Christ was and is truly cosmic.  It was the Eternal Christ who actually created the universe and who maintains its existence by the power of His word.  It is Jesus (centuries before He was born in Bethlehem) who often appears in the Old Testament's historical writings as the Angel of the Lord.  It is Jesus who paid for all sin of all time.  And it is Christ Himself who will one day return to the earth to reign as King.

There is much more about Jesus that I have no room to mention here.  You can read about Him in the Bible.  The Old Testament book of Isaiah has much to say about Him, hundreds of years before Mary gave birth.  The Gospels of John, Matthew, Mark and Luke talk about His earthly ministry.  The Book of Acts tells about how the church on earth was formed.  The letters of Paul, Peter, John and others in the New Testament explain many things in wonderful detail.  And the Book of the Revelation of Jesus reveals Christ as He truly is, in all eternity: the Lamb of God who was slain before the ages, and the Eternal King who will reign over all things for ever.