Musnad Ahmad 30:3748

Abu Sa'id narrated to us, Hammad bin 'Abbad as-Sadusi narrated to us, he said: I heard Abu al-Muhazzam narrating from Abu Hurairah, that the Prophet (peace and blessings of Allah be upon him): "Ordered that the 'Surahs of the Heavens' (al-Musabbihat) be recited in the 'Isha prayer."