Luke 2:8-9 (ESV)

And in the same region there were shepherds out in the field, keeping watch over their flock by night. And an angel of the Lord appeared to them, and the glory of the Lord shone around them, and they were filled with great fear.

Angels Announcing the Birth of Christ to the Shepherds, 1639
Govert Flinck (Dutch, 1615-1660)