Joy is what comes from the presence of the Lord and it is for those who know Jesus Christ as their personal Lord and Savior. Joy is different from happiness. Happiness has more to do with what is happening while the person who is filled with joy has something that transcends circumstances.
Psalm 16:9 You will make known to me the path of life;
In Your presence is fullness of joy;
In Your right hand there are pleasures forever.
Joy is connected to thanksgiving. It is a state of mind and heart of knowing that life is more than what is happening at any given moment. Joy is a gift that the Lord gives to His children through His Holy Spirit.
Galatians 5:22 But the fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness,
Joy can only come from the Lord and it is knowing that you are pleasing Him in your life and in your responses to life. It is a confirming from the Lord that you are in His will and doing what He delights in. When you are filled with joy it is almost as though you can feel His smile on your life. Your joy can be quenched through the old self, which is expressed in the flesh. The deeds of the flesh are not pleasing to the Lord so if you are involved in any of them then you will not have joy. The deeds of the flesh are evident when one is controlled by the flesh.
Galatians 5:19-21 Now the deeds of the flesh are evident, which are: immorality, impurity, sensuality, idolatry, sorcery, enmities, strife, jealousy, outbursts of anger, disputes, dissensions, factions, envying, drunkenness, carousing, and things like these, of which I forewarn you, just as I have forewarned you, that those who practice such things will not inherit the kingdom of God.
The nonChristian will use artificial means to try to be happy because they do not have the Spirit of God living within them. Artificial means, such as wine, drugs, etc., are very superficial and will not last but will only leave the one feeling more empty. When a Christian engages in any of these activities then they will quench the Holy Spirit who has come to live within them.
I Thessalonians 5:16-19 Rejoice always; pray without ceasing; in everything give thanks; for this is God’s will for you in Christ Jesus. Do not quench the Spirit;
The way that a Christian can be continually filled with joy is to continually walk in the Spirit. Walking in the Spirit keeps the Christian from being controlled by the flesh and expressing the deeds of the flesh.
Galatians 5:16,17 But I say, walk by the Spirit, and you will not carry out the desire of the flesh. For the flesh sets its desire against the Spirit, and the Spirit against the flesh; for these are in opposition to one another, so that you may not do the things that you please.
We are to please the One who lived and died for us. When we live according to His ways then our hearts will be filled with the joy of the Lord and how sweet it is. You will also find that thanksgiving and joy go together. Your heart will also be filled with much gratitude. What a contrast to those who do not know the Lord and who are always complaining.