“Rejoice in the LORD, O ye righteous: for praise is comely for the upright.” Psalm 33:1 (KJV)
This Psalm has no noted author. It could be David, or another, since most likely David is not the only one who wrote songs or Psalms. We know the words of praise and rejoicing in the LORD are inspired by GOD.
To rejoice in the LORD is an act. You might call it a work, but it is a work of righteousness which comes from a godly heart. To “Rejoice” is to lift up your voice in song, or to shout aloud, because you are overwhelmed by a jubilant thought, heart, and/or an experience with our God and Saviour.
Some may question, “Who are the righteous?” The short answer to that is – they are those who have been redeemed by the blood of the Lamb, and the Lamb is the Lord Jesus Christ.
Where “Rejoice” is a verb above meaning it is an action we take; the word “Praise” is a noun, and would mean this is the life of the righteous and it is beautiful. “Praise” is adoration, thanksgiving to God. To whom else would we offer praise.
Rejoice in God your Saviour, and live in praise to Him. That is the life of the “Upright”, and it is beautiful.