Musnad Ahmad 30:1519

Hassan and ‘Affan—the meaning being the same—narrated to us, they said: Hammad narrated to us, from ‘Ali ibn Zayd—‘Affan said: Hammad narrated to us, ‘Ali ibn Zayd informed us—from Abu al-Salt, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "On the night I was taken on the Night Journey (Isra’), when we reached the seventh heaven, I looked above—‘Affan said: above me—and behold, I was with thunder, lightning, and thunderbolts." He said: "Then I came upon a people whose bellies were like houses, in which were snakes that could be seen from the outside of their bellies. I said: 'Who are these, O Jibril?' He said: 'These are those who consume usury.'" "Then, when I descended to the lowest heaven, I looked below me, and behold, I was with dust, smoke, and voices. I said: 'What is this, O Jibril?' He said: 'These are the devils hovering over the eyes of the children of Adam, so that they do not reflect upon the kingdom of the heavens and the earth. And were it not for that, they would have seen wonders.'"