John 8:58 (NKJV)
Jesus said to them, "Most assuredly, I say to you, before Abraham was, I AM."
Jesus was born of a woman and so as a human he began to exist at that point in time. But Jesus' existed prior to that as God himself, the second member of the Trinity, God the Son. "I AM" is the name God gave when Moses asked him what His name was. Thus Jesus is identifying himself with God. Notice the aspect of eternity in the present tense of the statement. Eternity does not have a past and a future, no beginning nor end. Appropriately we can only speak of the eternal now.
Micah 5:2 (NKJV)
"But you, Bethlehem Ephrathah, Though you are little among the thousands of Judah, Yet out of you shall come forth to Me The One to be Ruler in Israel, Whose goings forth are from of old, From everlasting."