What is the authenticity of the story about the king who wanted to give half his kingdom for a drink of water, and the other half for the ability to urinate, whereupon the righteous man said to him: "I have no need for a kingdom that is worth a drink of water and a urination"?

This story has not been narrated with these exact words, but something similar has been reported in history books. Ibn Al-Sammak entered upon Al-Rashid and asked him: "If this drink of water were withheld from you, for how much would you buy it?" He replied: "For half my kingdom." When he drank it, he asked him: "If its exit from your body were prevented, with what would you buy it?" He replied: "With my entire kingdom." Ibn Al-Sammak then said: "Indeed, a kingdom whose value is a drink of water and a urination is truly not worth competing for." Harun then wept.