In Jesus is fullness of joy.
1 John 1:4 And these things we write to you that your joy may be full.
Here is the first of several reasons for Johns letter. That our joy may be full. To experience a joy filled life, which is far greater than happiness, which is temporal. I love how joy hangs around even in the midst of pain and hurt? Joy is not dependent on our circumstances. The world around us think it strange we dont cave to external problems. Things & events that would destroy most, we draw strength from the LORD.