'Angel of the Lord' in the Bible

three years of famine, or three months of devastation by your foes with the sword of your enemy overtaking you, or three days of the sword of the Lord—a plague on the land, the angel of the Lord bringing destruction to the whole territory of Israel.’ Now decide what answer I should take back to the One who sent me.”

Then God sent an angel to Jerusalem to destroy it, but when the angel was about to destroy the city, the Lord looked, relented concerning the destruction, and said to the angel who was destroying the people, “Enough, withdraw your hand now!” The angel of the Lord was then standing at the threshing floor of Ornan the Jebusite.

When David looked up and saw the angel of the Lord standing between earth and heaven, with his drawn sword in his hand stretched out over Jerusalem, David and the elders, clothed in sackcloth, fell down with their faces to the ground.

So the angel of the Lord ordered Gad to tell David to go and set up an altar to the Lord on the threshing floor of Ornan the Jebusite.