Christian joy is the proper response to the presence of something desirable: God.
– Philip Kenneson

The joy of the Lord will arm us against the assaults of our spiritual enemies, and put our mouths out of taste for those pleasures with which the tempter baits his hooks.
– Matthew Henry

Joy is diminished…by walking at a distance from God. 
If you get away from the fire you will grow cold.
– Charles Spurgeon

Christ being present with you, this is your main joy.  Enjoy the feast for yourselves,
or you will not be strong to hand out the living bread to others.
– Charles Spurgeon

Search the Scriptures diligently, and your joy shall spread and deepen.
– Charles Spurgeon

All the writings of Scripture, doctrinal, experimental, or practical, all have for their object, that which John declares in these words – “that your (our) joy may be full.”
– Charles Spurgeon