Joy is not fleeting happiness, but a steady source of satisfaction rooted in an eternal outcome - not a temporary circumstance.
The Suffering Servant
The king and kingdom of Israel seemed to be something of the past. They were in exile, and every king they ever had failed them - even the best of them had passed away. God continued to speak through prophets to let His people know He was still pursuing them. Through the prophet Isaiah, the Lord told them that one day the promised Rescuer would come and take away their sorrow and suffering - and that he would take it upon himself. We can have joy because this Suffering Servant has taken our sorrow.
The Spirit of the Lord is on Me
The good news of Jesus is often not what we expect. His words were often shocking to people and difficult to understand. Jesus often approached what God’s people thought they knew, and revealed an even deeper and better meaning behind them.
In Luke 4, Jesus stands in the synagogue reading from Isaiah's words centuries before. He is the fulfillment of those long awaited words promised, and yet it is unlike anything expected.