Summary of passage: The servant of the Lord tells the world to listen: Before the servant was born the Lord called him and gave him the authority for the right moment in time. The servant says, “I will display God’s splendor. Even though my labors are in vain, my reward is with God. I will bring Jacob back to the Lord and gather Israel up. I will also be a light for the Gentiles so I can bring God’s salvation to the ends of the Earth.”
3a) Before the servant was born, the Lord called him and has made mention of his name from birth. The servant’s words will have power and authority and be ready when needed.
b) To display God’s splendor. To bring Jacob back to him, to gather Israel to himself, be a light for the Gentiles and being God’s salvation to the ends of the Earth.
4a) The servant says His labor is in vain and has no purpose; yet, he recognizes his reward is with God. God is his strength despite the enormity and sometimes rejection of his task.
b) Jesus. Micah 5:2-5 “But you, Bethlehem,.. out of you will come for me one who will be ruler over Israel whose origins are from of old, from ancient times. Therefore Israel will be abandoned until the time when she who is in labor gives birth…He will stand and shepherd his flock in the strength of the Lord…for then his greatness will reach to the end of the earth.”
Romans 11:25-27 “…Until the full number of the Gentiles has come in. And so all Israel will be saved, as it is written: ‘The deliverer will come from Zion; he will turn godlessness away from Jacob. And this is my covenant with them when I take away their sins.”
Conclusions: Most commentators agree this passage is about Jesus. Interestingly, my Bible says it is Israel (as well as some others I found on the internet), citing Genesis 22:18 as reasoning since God’s original covenant was for Israel to bring salvation to the ends of the earth.
I believe it’s Jesus since Jesus is the King of the Jews (Israel) so, in this instance, Jesus can be referred to as Israel. The rest of the descriptions of the Servant is overtly Messianic. I found this very interesting analysis that dissects the question both ways and comes to the conclusion that this can only be the Messiah: