Joy of the Lord

Joy is the belief, based on the testimony of the Word and Spirit of God, that we, or someone we love, is, or soon will be 

Sorrow is the opposite of joy.

There will be more rejoicing in heaven over one sinner who repents than over ninety-nine righteous persons who do not need to repent. (Luke 15:7)

John records what Jesus taught the disciples so that Jesus’ joy might remain in them and that their joy might be full (complete and undiminished). (John 15:11) What did he teach them? Starting in John 14 Jesus taught his disciples about living in unity with God through abiding in him, bearing fruit that glorifies God, and being led by the Spirit of truth.

Whatsoever you ask in my name, that will I do, that the Father may be glorified in the Son. If you ask anything in my name, I will do it. (John 14:13-14)

Until now have you asked nothing in my name: ask, and you shall receive, that your joy may be full. (John 16:24)

It gave me great joy to have some brothers come and tell about your faithfulness to the truth and how you continue to walk in the truth. I have no greater joy than to hear that my children are walking in the truth. (3 John 1:3-4)

Joy of the Lord is our strength (Nehemiah 8:10) - the strength to overcome and endure against forces working to draw us from unity and fruitfulness.

Consider it all joy, my brethren, when you encounter various trials, knowing that the proving of your faith works patience. And let endurance have its perfect result, so that you may be mature and complete, lacking in nothing. (James 1:1-3)

Through James, God tells us that trials prove our faith and these are the conditions under which we become more fruitful. This works so that we receive spiritual maturity and so that we receive everything we need.

The one on whom seed was sown on the rocky places, this is the man who hears the word and immediately receives it with joy; yet he has no firm root in himself, but is only temporary, and when affliction or persecution arises because of the word, immediately he falls away. (Matthew 13:20-21)

Hearing the word of God produces joy - believing that we are living in unity with God and bearing fruit that glorifies him. Affliction and persecution come to prove our faith and the joy that is produced by our faith. They overcome the person whose belief is not rooted in the testimony of the Word and Spirit of God. They may also overcome the person who fails to understand that affliction and persecution sometimes accompany the conditions under which we receive blessing - conditions under which we become compacted in unity with God and become more fruitful. We overcome the forces of affliction and persecution by taking our eyes off of them and look ahead to the increased unity and fruitfulness: to the joy set before us. 

Let us run with patience the race that is set before us, Looking to Jesus the author and finisher of our faith; who for the joy that was set before him endured the cross, despising the shame, and is set down at the right hand of the throne of God. (Hebrews 12:1-2)

For the joy (of the Lord) that was set before him Jesus endured the cross. He believed that, relying on God and the way God revealed to him, by his stripes we would be healed, by his shed blood we would be cleansed from sin, by suffering death he would pay the redemption price to free all man and creation from Satan. For the joy of bringing forth fruit that frees us from sin and death and brings us into a life of joy, Jesus endured the cross.

Joy works in prayer when we believe, based on the testimony of the Spirit of truth, that we are living in unity with God and we bring forth fruit that glorifies him when receive what we desire and ask for in prayer. The faith in our prayer will be tested and when it is proven genuine we have what we ask.

What things soever you desire, when you pray, believe that you receive them, and you shall have them. (Mark 11:24)

Believing we receive what we have asked for in prayer is joy and should produce a joyful expectation bring forth fruit that glorifies God. Joy is the normal fruit of believing we receive and will be the natural result of true faith.