Joy comes from:
Loving God
Psalm 5:11 let those also who love Your name be joyful in You.
Being in His presence
Psalm 16:11 You will show me the path of life; in Your presence is fullness of joy
His faithfulness
Isaiah 61:10 I will greatly rejoice in the Lord, my soul shall be joyful in my God; For He has clothed me with the garments of Salvation, He has covered me with the robe of righteousness..
His Word
Jeremiah 15:16 Your words were found, and I ate them, and Your word was to me the joy and rejoicing of my heart; for I am called by Your name, O Lord God of hosts.
Being refreshed in the Lord
Act 8:5-6, 8 Then Philip went down to the city of Samaria and preached Christ to them. And the multitudes with one accord heeded the things spoken by Philip, hearing and seeing the miracles which he did. And there was great joy in that city.
