The Opposite of "Rejoice"

Pastor is always talking about rejoicing, even in the midst of trouble. 

So. Hard. To. Understand.

In my mind, the opposite of "rejoice" is "grieve."
You know -- if you're not happy, then you're sad.

So when you run across a passage like 1 Thessalonians 1:6 ("You received the word in much affliction, with joy in the Holy Spirit"), it messes with my mind.  So I asked a simple question:  "What is the opposite of rejoice?" 

The answer?  "Despair."

Grieving and suffering and hurting and sorrow are NOT the opposite of joy.  Despair is.  Hopelessness is.  Giving-up-on-God's-mercy is the opposite of "rejoice."

Now things are beginning to make sense.