I will praise the LORD according to His righteousness, And will sing praise to the name of the LORD Most High.
This Psalm is essentially a diatribe regarding the words and actions of Cush, a Benjamite an evil man whom David did not admire. I was unable to find out more about him, the Spirit didn't find it necessary to enlighten me further.
However, the total lesson, I believe is contained in the last verse. “No matter what challenges and setback I have to face, I will praise the LORD. A hard lesson to learn, the old man in me wants to rant and rave.
Reading
Morning Psalm 86, Noon Psalm 119:1-8, Evening Psalm 26