The answer is: An angel

Luke 1:13 - Gabriel, from Luke 1:19.

When we turn to Luke 1, we encounter the intriguing story of Zacharias and his wife, Elizabeth, who were both advanced in age and childless. Just imagine the surprise when the angel Gabriel wings into the scene to deliver such stellar news! Gabriel doesn't just pop in for a cheerful chat; he boldly interrupts the ordinary working life of a priest to deliver a divine message.

Fun fact: Gabriel's appearances in the Bible are quite noteworthy! He didn't just casually show up—Gabriel makes a grand entrance at pivotal moments. Besides this announcement of John the Baptist’s birth, he also told Mary that she'd be the mother of Jesus—an angel with some serious responsibilities!

This moment marks not just a personal miracle for Zacharias and Elizabeth, but also a profound pivotal moment in biblical history, preparing the way for the emergence of a remarkable prophet. This is particularly significant in Luke’s narrative as he emphasizes the theme of promise and fulfillment.

Also, if we peek into the wider context of the Hebrew scriptures, angels like Gabriel carry the weight of God’s messages. Historically revered sources of divine information, they often appear during transformative times — a reminder that everyone, no matter their age or status, can be touched by holy grace. Like courageous messengers, these beings stood as agents of change, ushering in new beginnings for those willing to listen. So, keep an eye out; profound surprises can come to us in the most ordinary of hours!