“Daughter Zion.” The Hebrew is idiomatic for Zion itself, i.e., Jerusalem (see commentary on Isa. 1:8).
“Daughter Jerusalem.” The Hebrew structure and idiom is similar to that of “Daughter Zion” (see commentary on Isa. 1:8). Here in 2 Kings 19:21 (and also Isaiah 37:22), Jerusalem is referred to twice in the verse by two different names, “Daughter Jerusalem” and “Daughter Zion.” It is typical of Hebrew poetry to refer to the same thing in two different ways.
2 Kings 19:21 and Isaiah 37:22 are a good portrayal of God showing that with His help great feats can be accomplished and horrible and impossible-looking situations can be turned into great victories. Jerusalem is portrayed as a young woman, a virgin daughter, thus likely in her early teens, being approached by the “big, bad man,” Assyria, who is intent on raping and pillaging her the same way he raped and destroyed her sister, the Northern Kingdom of Israel. Yet with God’s help she defies him, ridicules him, and shakes her head at him. She trusts God, and God, her protector, steps in and takes care of the situation. Ultimately those who trust in God will always have the victory, even over death. “Thanks be to God, who gives us the victory through our Lord Jesus Christ” (1 Cor. 15:57; cp. 1 Cor. 15:54-57).