Musnad Abu Ya'la al-Mawsili 6:57

Ibrahim ibn Sa'id narrated to us, Abu Fulan narrated to us, Abu Bakr ibn Abi Maryam narrated to us, from Rashid ibn Sa'd, from Sa'd ibn Abi Waqqas, who said: The Messenger of Allah (peace and blessings of Allah be upon him) was asked about this verse: "Say, 'He is the [one] capable of sending upon you affliction from above you or from beneath your feet'" (Al-An'am: 65). The Messenger of Allah (peace and blessings of Allah be upon him) said: "As for it, it is going to happen, and its interpretation has not yet come."