It was narrated that 'Abdullah bin Mas'ud said: "If the people of knowledge had taken care of it and presented it only to those who cared for it, they would have become the leaders of their age by virtue of that. But they squandered it on the people of wealth and status in this world in order to gain some worldly benefit, so the people of wealth and status began to look down on them. I heard your Prophet say: 'Whoever focuses all his concerns on one issue, the concerns of the Hereafter, Allah will suffice him and spare him the worries of this world. But whoever wanders off in concern over different worldly issues, Allah will not care in which of these valleys he is destroyed.'" (Da'if) Another chain with similar wording.