The fight for joy in Christ is not a fight to soften the cushion of Western comforts. It is a fight for strength to live a life of self-sacrificing love. It is a fight to join Jesus on the Calvary road and stay there with him, no matter what. How was he sustained on that road? Hebrews 12:2 answers, “For the joy that was set before him [he] endured the cross.” The key to endurance in the cause of self-sacrificing love is not heroic willpower, but deep, unshakable confidence that the joy we have tasted in fellowship with Christ will not disappoint us in death. Sacrifices in the path of love were sustained in the New Testament not by willpower, but by joyful hope. “You had compassion on those in prison, and you joyfully accepted the plundering of your property, since you knew that you yourselves had a better possession and an abiding one” (Heb. 10:34).
John Piper, When I Don’t Desire God: How to Fight for Joy.pp 20-21.