Musnad Ahmad 30:1561

Sulayman ibn Dawud narrated to us, Ismail—meaning Ibn Ja'far—narrated to us, he said: Al-'Ala'—who is Ibn 'Abd al-Rahman—informed me, from his father, from Abu Hurayrah, that the Messenger of Allah (peace and blessings of Allah be upon him) said—and Ubayy recited the Mother of the Qur'an to him—: "By the One in Whose hand is my soul, nothing like it has been revealed in the Torah, nor in the Gospel, nor in the Psalms, nor in the Criterion (the Furqan). It is the seven oft-repeated verses and the Great Qur'an which I have been given."