John Gill Commentary Isaiah 52:6

"Therefore my people shall know my name: therefore [they shall know] in that day that I am he that doth speak; behold, it is I." — Isaiah 52:6 (ASV)

Therefore my people shall know my name His nature and perfections; his faithfulness in fulfilling his promises to them; his power in delivering them out of their bondage; and his justice in punishing their enemies.

Therefore they shall know on that day that I am he that speaks: behold, it is I; they shall then see, when the people of God are delivered from the antichristian slavery and bondage, and when Babylon is fallen, that all the promises God has spoken are yea and amen; that Jesus Christ is the true and faithful witness; and that these are his true and faithful sayings, which he has spoken.