I heard a preacher say once that you can be joyful, even if you aren't happy. I don't see how that's possible, because if I'm not happy, then I'm certainly not joyful. Maybe you can explain what he might have meant.
What he said is true: We can be joyful, even when our circumstances are bad and life has turned against us.
You see, there’s a difference in the Bible between happiness and joy. Happiness depends on our outward circumstances; if everything is going well, then we’re probably happy. Unfortunately the opposite is also true; if things aren’t going well for us, then we’ll probably be unhappy. It’s not wrong to seek happiness, of course; happiness is one of God’s gifts. The writer of Ecclesiastes declared, “I know there is nothing better for men than to be happy and do good while they live” (Ecclesiastes 3:12).
But even when life turns against us, we can still be joyful in our hearts. How is this possible? It’s possible when we realize that God still loves us, and that no matter what happens to us, He is with us and we still belong to Him. I seriously doubt if the Apostle Paul enjoyed being put in prison for his faith, but even there he could rejoice because his hope was in Christ, not in his circumstances. While in prison he wrote, “Rejoice in the Lord always. I will say it again: Rejoice!” (Philippians 4:4).
Put your faith and trust in Christ — both when times are good, and when they are bad. When your hope is in Him, you’ll discover the reality of true joy — joy that comes not from your circumstances, but from His Spirit living within you. “Let the righteous rejoice in the Lord and take refuge in him” (Psalm 64:10).