Who is the Lord of Heaven's Armies?

“For this is what the Lord of Heaven’s Armies says: In just a little while I will again shake the heavens and the earth, the oceans and the dry land.  I will shake all the nations, and the treasures of all the nations will be brought to this Temple. I will fill this place with glory, says the Lord of Heaven’s Armies." Haggai 2:6 NLT