'Messenger' in the Bible

"Climb up a high mountain, you messenger of good news to Zion! Lift up your voice with strength, you messenger to Jerusalem! Lift it up! Don't be afraid! Say to the towns of Judah, "Here is your God!'

First, to Zion: "There is slumber." And to Jerusalem: "I'll send a messenger with good news."

Who is blind except my servant, or deaf like my messenger I am sending? Who is blind like the one committed to me, or blind like the LORD's servant?