Then Nehemiah told them, “Go and eat what is rich, drink what is sweet, and send out portions to those who have nothing prepared, since today is holy to our Lord. Do not grieve, for the joy of the LORD is your strength.” — Nehemiah 8:10

This isn't your joy in the Lord but His joy in you—it's the same stream. Sing for joy, for the Lord has comforted His people. He is your strength and your song. Rejoice always, not because circumstances are good, but because He is.