Psalms 93, 97 and 99 begin with the expression "The Lord Reigneth" and end with a mention of God's holiness.  These psalms are sometimes called "enthronement psalms" or "theocratic psalms" by Bible scholars.  They celebrate the Lord's reign on the earth.

Psalm 93 - Confidence of His Reign
Psalm 97 - Constitution of His Righteousness
Psalm 99 - Character of His Rule 
 
Read Part 1, Part 2.