Scripture tells us that Jesus endured the pain and shame of the cross "...for the joy set before him." What joy could there possibly be in the cross? The answer is found in one word, a word Jesus uttered from the cross: Tetelestai.
It is finished. That's what Tetelestai means. The joy of the cross is the joy of "Tetelastai," the joy of completing the mission proclaimed by his very name, which means, "He will save his people from their sins." And that he did. It is finished!