*FYI -I added the rest of the 'Fruitages of the Spirit' symposium parts from the District Convention to my downloads page. (The following info is from pgs 119-121 of Insight on the Scriptures Vol. 2)
The emotion excited by the acquisition or expectation of good; state of happiness; exultation. The Hebrew and Greek words used in the Bible for joy, exultation, rejoicing, and being glad express various shades of meaning, different stages or degrees of joy. The verbs involved express the inner feeling and the outward manifestation of joy and variously mean “be joyful; exult; shout for joy; leap for joy.”
Jehovah God and Jesus Christ
Jehovah is called “the happy God.” (1Timothy 1:11) He creates and works with joy for himself and his creatures. What he brings about makes him joyful. (Psalm 104:31) He wants his creatures likewise to enjoy his works and to enjoy their own work. (Ecclesiastes 5:19) Since he is the Source of all good things (James 1:17), all intelligent creatures, both mankind and angels, can find their chief enjoyment in coming to know him. (Jeremiah 9:23, 24) King David said: “Let my musing about him be pleasurable. I, for my part, shall rejoice in Jehovah.” (Psalm 104:34) He also sang: “The righteous one will rejoice in Jehovah and will indeed take refuge in him; and all the upright in heart will boast.” (Psalm 64:10) The apostle Paul urged Christians to take joy at all times in their knowledge of Jehovah and his dealing with them, writing to them: “Always rejoice in the Lord [“Jehovah,” in several versions]. Once more I will say, Rejoice!”—Philippians 4:4.
Jesus Christ, who was the intimate one of Jehovah, knows him best (Matthew 11:27), and he is able to explain Him to his followers. (John 1:18) Jesus is therefore joyful, being called “the happy and only Potentate.” (1Timothy 6:14, 15) Out of love for his Father, he is eager to do always the things that please Him. (John 8:29) Therefore, when there was set before him the task of coming to earth, suffering, and dying in order that he might vindicate Jehovah’s name, “for the joy that was set before him he endured a torture stake, despising shame.” (Hebrews 12:2) He also had great love for and joy in mankind. The Scriptures, personifying him in his prehuman existence as wisdom, represent him as saying: “Then I came to be beside [Jehovah] as a master worker, and I came to be the one he was specially fond of day by day, I being glad before him all the time, being glad at the productive land of his earth, and the things I was fond of were with the sons of men.”—Proverbs 8:30, 31.
Jesus desired his followers to have the same joy, telling them: “These things I have spoken to you, that my joy may be in you and your joy may be made full.” The angels had joy at the creation of the earth. (John 15:11; 17:13; Job 38:4-7) They also view the course of God’s people, taking joy in their faithful course and especially exulting when an individual turns from his sinful ways to the pure worship and service of God.—Luke 15:7, 10.
What makes God joyful
Jehovah’s heart can be made glad by his servants because of their faithfulness and loyalty to him. Satan the Devil has constantly challenged the rightfulness of God’s sovereignty and the integrity of all those serving God. (Job 1:9-11; 2:4, 5; Revelation 12:10) To them apply the words: “Be wise, my son, and make my heart rejoice, that I may make a reply to him that is taunting me.” (Proverbs 27:11) Jehovah’s people in the earth can cause God to rejoice by faithfulness and loyalty to him.—Isaiah 65:19; Zephaniah 3:17.
A Fruit of the Spirit
Since Jehovah is the Source of joy and he desires joyfulness for his people, joy is a fruit of his holy spirit. Joy is named immediately after love in the list at Galatians 5:22, 23. The apostle wrote to the Christians at Thessalonica: “You became imitators of us and of the Lord, seeing that you accepted the word under much tribulation with joy of holy spirit.” (1Thessalonians 1:6) Accordingly, Paul counseled the Christians at Rome that the Kingdom of God “means righteousness and peace and joy with holy spirit.”—Romans 14:17.
True joy is a quality of the heart and can affect the whole body for good. “A joyful heart has a good effect on the countenance,” and “a heart that is joyful does good as a curer [or, “does good to the body”],” says the wise writer of Proverbs.—Proverbs 15:13; 17:22, ftn.
Joy in God’s Service
What Jehovah asks of his servants is not burdensome. (1John 5:3) He wants them to enjoy his service. His people Israel were to enjoy the seasonal festivals that he arranged for them, and they were to rejoice in other aspects of their life and worship of God. (Leviticus 23:40; Deuteronomy 12:7, 12, 18) They were to speak out about God joyfully. (Psalm 20:5; 51:14; 59:16) If they did not serve with joy of heart, there was something wrong with their hearts and their appreciation of his loving-kindness and goodness. Therefore he warned what would take place if they became disobedient and took no joy in serving him: “All these maledictions will certainly come upon you . . . because you did not listen to the voice of Jehovah your God by keeping his commandments and his statutes . . . And they must continue on you and your offspring . . . due to the fact that you did not serve Jehovah your God with rejoicing and joy of heart for the abundance of everything.”—Deuteronomy 28:45-47.
The Christian, no less, should enjoy his service to God. Otherwise, something is lacking in heart appreciation. (Psalm 100:2) “The joy of Jehovah is your stronghold,” said one of God’s faithful servants. (Nehemiah 8:10) The good news the Christian proclaims was announced by God’s angel as “good news of a great joy that all the people will have.” (Luke 2:10) Jehovah’s name upon his witnesses and the truth as found in the Bible should themselves be a joy to them. The prophet Jeremiah said: “Your word becomes to me the exultation and the rejoicing of my heart; for your name has been called upon me, O Jehovah God of armies.”—Jeremiah 15:16.
Moreover, Jehovah’s just, right judicial decisions put into effect in the Christian congregation and in the lives of Christians are cause for joy, especially in a time when the world has thrown justice and righteousness to the ground. (Psalm 48:11) Then, too, the marvelous hope ahead surely gives strong ground for joyfulness. (“Rejoice in the hope”; Romans 12:12; Proverbs 10:28.) Their salvation is a basis for joy. (Psalm 13:5) Additionally, there is the joy that the servant of God has in those whom he aids in coming to the knowledge and service of Jehovah. (Philippians 4:1; 1Thessalonians 2:19) Meeting together and working together with God’s people is one of the greatest joys.—Psalm 106:4, 5; 122:1.
Persecution a cause for joy
For the Christian who guards his heart, even persecution, though not in itself enjoyable, should be viewed with joy, for endurance of it with integrity is a victory. God will help the faithful one. (Colossians 1:11) Additionally, it is proof that one is approved by God. Jesus said that when reproach and persecution come, the Christian should “leap for joy.”—Matthew 5:11, 12; James 1:2-4; 1Peter 4:13, 14.
Other Joys Provided by God
Jehovah has provided many other things that mankind may enjoy day by day. Some of these are marriage (Deuteronomy 24:5; Proverbs 5:18), being father or mother of a righteous and wise child (Proverbs 23:24, 25), food (Ecclesiastes 10:19; Acts 14:17), wine (Psalm 104:14, 15; Ecclesiastes 10:19), and the multitudinous things of His creation (James 1:17; 1Timothy 6:17).
False or Nonlasting Joys
Jesus speaks of some who would hear the truth and receive it with joy but without getting the real sense of it. Such do not cultivate the implanted word in their hearts and, as a consequence, soon lose their joy by being stumbled when tribulation or persecution arises on account of the word. (Matthew 13:20, 21) Joy based on materialism is a false joy that is in error and will be short-lived. Also, a person rejoicing over the calamity of another, even of one who hates him, must account to Jehovah for his sin. (Job 31:25-30; Proverbs 17:5; 24:17, 18) A young man is foolish to think that enjoyment of life requires that he give in to following “the desires incidental to youth.” (2Timothy 2:22; Ecclesiastes 11:9, 10) Similarly, love of merriment will bring one into a bad situation. (Proverbs 21:17; Ecclesiastes 7:4) Even the Christian who exults in comparing himself with others is in error. Rather, he should prove what his own work is and have cause for exultation in himself alone.—Galatians 6:4.
Jehovah promised to restore his people Israel after their exile in Babylon. He did bring them back to Jerusalem in 537 B.C.E., and they greatly rejoiced when the temple foundation was laid. (Isaiah 35:10; 51:11; 65:17-19; Ezra 3:10-13) But Isaiah’s prophecy (65:17) has a greater fulfillment in the establishment of “a new heaven and a new earth,” in which arrangement all mankind will have joy forever under the “New Jerusalem.”—Revelation 21:1-3.
Under present conditions, wickedness, sickness, and death prevent full and undiminished joy. But in harmony with the Bible rule, “A wise king is scattering wicked people,” Jesus Christ as King will bring an end to all enemies of God and of righteousness. (Proverbs 20:26; 1Corinthians 15:25, 26) Thus all obstacles to complete joy will be removed, for even “death will be no more, neither will mourning nor outcry nor pain be anymore.” (Revelation 21:4) Sorrow for those who have died will be completely gone, removed by the resurrection of the dead. This knowledge comforts Christians even today, who, on this account, do not “sorrow just as the rest also do who have no hope.”—1Thessalonians 4:13, 14; John 5:28, 29.
*here's one of my favorite passages that helps to keep in mind when we have to deal with trialsome situations which can rob us of joy:
(Psalms 126:3, 5, 6)
"Jehovah has done a great thing in what he has done with us.
We have become joyful . . .
Those sowing seed with tears
Will reap even with a joyful cry.
The one that without fail goes forth, even weeping,
Carrying along a bagful of seed,
Will without fail come in with a joyful cry,
Carrying along his sheaves."