It's super hard to know who's speaking here: Is it Isaiah? All of Israel? the as-of-yet unrealized servant, come to save all of Israel? Cyrus, King of Persia?
The servant, whoever he is, compares himself to an arrow readied and placed in quiver, waiting for a time to strike. His mouth was made like a sword, because of its ability to speak words that would destroy wickedness. So much for "sticks and stones can break my bones, but words can never hurt me."
God calls him his servant, the representative of all Israel. But Isaiah says that he's labored in vain, having failed to change anything—though his reward lies with God.
Nonetheless, God has appointed the servant to save the House of Jacob, and to be a light to all the other nations, as well. God says that all the pagan and Gentile kings will end up falling down to pay reverence to God and to Israel.
God says that he's given his servant the mission of dragging the (metaphorical) prisoners out of the darkness and into the light, allowing them to roam freely in the world without hungering or thirsting.
He promises to guide people from all over towards the right way, leveling mountains and creating a holy road everyone can travel on.
All of nature should rejoice (the mountains are ordered to burst into song) because of how God will comfort the sufferings of people.
Zion thinks God has rejected it, but in reality, God can't forget it any more than a woman can forget her own newborn baby—although God says he's actually even more reliable than that, he says.
The constructive people in Israel outnumber its destructive people. So it'll all get better. Even though it seems destroyed for now, it will soon be crowded with inhabitants again.
Finally, God promises all the nations will start being nice to Israel, instead of trying to sack and destroy it. They'll play with Israel's children, act as foster fathers and mothers to the country as a whole, buy them nice Playstations, and bow down to them in reverence.
Those who wait for God's promise to be fulfilled won't be disappointed. He'll destroy the tyrants and oppressors, and everyone will know that he's really God.