What is Joy?

Merriam-Webster’s online dictionary defines it this way:

joy noun \ˈjȯi\ -

1. a :  the emotion evoked by well-being, success, or good fortune or by the prospect of possessing what one desires : delight
   b :  the expression or exhibition of such emotion : gaiety

2. a state of happiness or felicity : bliss

3. a source or cause of delight

joy verb -

1. :  to experience great pleasure or delight : rejoice

2. archaic : gladden

3. archaic : enjoy

The Bible speaks of both joy and happiness.  Many times we are told to rejoice, and Jesus teaches on having fullness of joy.  Yet Jesus also taught in the sermon on the mount many ways to be blessed, or happy.  Joy is usually described as something which cannot be taken away when circumstances change, while happiness is based on circumstances entirely.  One site describes it this way: 

Happiness is an emotion in which one experiences feelings ranging from contentment and satisfaction to bliss and intense pleasure. Joy is a stronger, less common feeling than happiness.  {source – not necessarily recommended}

I think the difference between the two will be more clearly seen as we continue to study where joy comes from, and how and when God instructs us to have joy.

“Our joys on earth we are liable to be robbed of by a thousand accidents, but heavenly joys are everlasting.” 
--Matthew Henry