Musannaf Ibn Abi Shayba 33:1112

Yahya ibn Abi Bukayr narrated to us, he said: Ibrahim ibn Nafi’ narrated to us, from Ibn Tawus, from his father, who said: The sweetness of the world is the bitterness of the Hereafter, and the bitterness of the world is the sweetness of the Hereafter.