This is the climax of the first section: the summary of what a good king must do. It pairs speech ('open thy mouth'), justice ('judge righteously'), and advocacy ('plead the cause of the poor and needy'). These three are not separate; they work together. True justice speaks, acts fairly, and champions the vulnerable.
Memory phrase: Be fair. Help others.
Talk about it: What does it mean to stand up for someone who needs help?
Prayer: God, make me someone who speaks up rightly.