In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Once after Haaroon Ar-Rasheed [may Allaah have mercy upon him] performed Hajj, he mentioned Bahlool [may Allaah have mercy upon him] as soon as he entered kufa and then said, “Dress him in a black garment, place a long headwear on his head and make him stay in such and such place”. The people did what Haaroon ordered them and then said to Bahlool, “When the leader of the believers arrives, supplicate for him”. When Haaroon came, Bahlool raised his head and said, “O leader of the believers! I ask Allaah to grant you provision and increase His favours on you”, so Haaroon laughed and said, “Aameen”. When Haaroon went past him, a person pulled Bahlool and said to him, “O insane one! Is this what you supplicate for the leader of the believers?” Bahlool said to him, “Keep quiet O insane one! There is nothing more beloved to the leader of the believers in the Dunyah than the Daraahim (i.e. wealth)”. When this statement reached Haaroon, he laughed and said, “By Allaah! He did not lie”.
[An Excerpt from Uqalaa Al-Majaaneen. Page 37. Slightly paraphrased]