What was “the joy that lay before Him”? Several possibilities fit well.
One possibility was the joy of returning home. Remember that Jesus left the indescribable glories of heaven and took on the form of a servant when He entered human life (Philippians 2). The prospect of returning to glory would certainly have been cause for great joy, and that is clearly represented in the cross.
Another possibility was the joy of finishing well. The cross represented a kind of finish line in the course Jesus had run. All His life on earth had been moving toward this. The cross was the culmination of his obedience to the Father. Finishing well always produces joy.
A third possibility is the joy of impact. Jesus knew that the cross and the resurrection to follow, when told to the world in the context of God’s love, forgiveness, and redemption, would bring those separated from God into the kingdom of God. People would enter a personal relationship with the Lord by faith. They would receive eternal life. There is no greater joy than seeing someone enter the kingdom of God.
Probably this joy was all the above. And more.
Maybe that's the kind of joy we need.
Lord, You are the Author, the Creator of joy, and Your Spirit the only real Source of joy. Thank You for the example You set in facing even the most horrible aspects of life with a joy that was indestructible by circumstances. Amen.