I've noticed a special quality of joy in the Christians of the New Testament.
"But recall the former days when, after you were enlightened, you endured a hard struggle with sufferings, sometimes being publicly exposed to reproach and affliction, and sometimes being partners with those so treated. For 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. Therefore do not throw away your confidence, which has a great reward. For you have need of endurance, so that when you have done the will of God you may receive what is promised" (Hebrews 10:32-36).
These early Christians were characterized by joy when they faced ridicule, cutting remarks, imprisonment, and the theft of their property. They were being persecuted for believing in Jesus Christ. But their joy could not be taken from them, because they had sincere faith and hope in the promises of God's word. They trusted their Savior and his word. Their joy was tough because their faith and hope in Christ were solid.
Their tough joy was a product of the Holy Spirit in their lives (Galatians 5:22). I want to see him produce it in the lives of all of us who follow Christ today as well.