'Angel of the Lord' in the Bible

Either three years of famine, or three months of reversals as you are swept away by your enemies while the sword of your enemies overtakes you, or three days with the sword of the LORD, consisting of pestilence infecting the land, with the angel of the LORD wreaking destruction from border to border throughout all of Israel.' Decide right now what I am to answer to the one who sent me."

So the angel of the ORD remained standing near the threshing floor that belonged to Ornan the Jebusite. David looked up and saw the angel of the LORD standing between earth and heaven, with a drawn sword in his hand stretched out over Jerusalem. Then David and the elders, clothed in sackcloth, fell on their faces.

The angel of the LORD told Gad to tell David that David was to go up and build an altar to the LORD on the threshing floor that belonged to Ornan the Jebusite.

but David was not going before it to inquire of God, because he was afraid of the sword carried by the angel of the LORD.