The answer is: An angel

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

When Zacharias received the astonishing news from the angel Gabriel, it was more than just a surprise. This scene is set against a backdrop rich in history and meaning. After several centuries of silence from prophets, the arrival of an angel was a huge buzz, not just for Zacharias but for the whole community. You see, the birth of John the Baptist was a pivotal moment, paving the way for Jesus.

Gabriel, whose name means "God is my strength," was no ordinary messenger. He boasted some serious street cred, having also appeared to the prophet Daniel in the Old Testament. His consistent role in significant announcements highlights the importance of the messages he delivered. However, Zacharias’ initial skepticism—that sense of doubt that even people of faith can sometimes harbor—was met with a gentle, albeit firm rebuke from Gabriel, emphasizing that God's plans often surpass our understanding.

Around this time in Israel’s history, many were waiting expectantly for a greater deliverance. Gabriel was not just announcing a pregnancy; he was announcing a restoration of hope. Isn’t it fascinating how John the Baptist’s birth marked the closeness of the divine to humanity? Interestingly, his mission would resonate with themes of repentance and preparation, ensuring that he would uniquely set the stage for an even greater miracle to come—Jesus.

Nothing was trivial in this far-reaching narrative, and it's clear that angels weren’t just celestial beings. They were harbingers of profound change!