What do you think of when I mention joy? Is it the thrilling victory of your favorite sports team? Perhaps it is a beautiful sunset or a new puppy?
A dictionary definition of joy is “a feeling of great pleasure and happiness”. Tim Keller tells us that joy is a deep sense of gladness that is not dependent on circumstances.
We may think that the opposite of joy is sadness. For example, I can be sad when my favorite team loses an important game, or when someone I love is suffering. Keller however says that the opposite of joy is not sadness, but hopelessness.
The word joy appears often in the Bible. For example, joy is a fruit of the Holy Spirit, as we read in Galatians 5:22-23:
But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law.

R.C. Sproul tells us that sometimes we struggle to grasp the biblical view of joy because of the way it is defined and described in Western culture today. In particular, we often confuse joy with happiness. Sproul states that the word happy in our culture has been sentimentalized and trivialized.
Another time that the Bible looks at joy is in the Apostle Paul’s letter to the Philippians. In Philippians 4:4, Paul speaks about joy and about the Christian’s duty to rejoice over and over again.
Rejoice in the Lord always; again I will say, rejoice.
Sproul tells us that Paul wrote this letter from prison, yet he tells the Philippian believers that they should rejoice despite his circumstances.

We can ask how it is possible to be joyful all of the time. Sproul tells us that the key to the Christian’s joy is its source, which is the Lord. He writes that if Christ is in me and I am in Him, that relationship is not a sometimes experience. The Christian is always in the Lord and the Lord is always in the Christian, and that is always a reason for joy.
There is much more that could be said about joy for the believer. For now, be encouraged by the below verses which deal with the subject of the Christians’ joy:

1 Thessalonians 5:16-18
Rejoice always, pray without ceasing, give thanks in all circumstances; for this is the will of God in Christ Jesus for you.  

Romans 12:12
Rejoice in hope, be patient in tribulation, be constant in prayer.

Psalm 118:24
This is the day that the Lord has made;
let us rejoice and be glad in it. 

Romans 12:15
Rejoice with those who rejoice, weep with those who weep. 

Romans 15:13
May the God of hope fill you with all joy and peace in believing, so that by the power of the Holy Spirit you may abound in hope.