Musannaf Ibn Abi Shayba 33:1042

Qutaybah ibn Sa'id narrated to us, he said: Ya'qub ibn 'Abd al-Rahman narrated to us, from Abu Hazim, that he said: A little of the world distracts from much of the Hereafter. Then he said: Indeed, you find a man occupying himself with the concern of another, to the point that he is more intense in concern than the one who actually possesses the concern himself.