What causes joy?

1 Peter 4:13 - Rejoice to the extent that you partake of Christ's sufferings, that when His glory is revealed, you may also be glad in His exceeding joy.

Why does the bible frequently speak of finding joy in suffering? Doesn't the writer know that trials are difficult and manytimes cause unbearble heartache?

Well in the verse above, we start to see a glimpse of the plan of God. He wants us to give Him all the glory and praises. You see, when you partake in Christ's sufferings, and pull through the hard times of struggles, God will reveal that He was there all along and you will praise Him. That is His desire, you praising Him. You will be glad in His exceeding joy and will be filled with joy as well.

Long story short, when you suffer, remember Jesus suffering as He died for your sins and give Him praise, which He deserves, and He will bless you with gladness and joy.