Musnad Ahmad 770:39

Muhammad ibn Ja'far narrated to us, Shu'bah narrated to us, from Isma'il, who said: I heard Qays ibn Abi Hazim narrating from Jarir, who said: We were with the Messenger of Allah, may Allah bless him and grant him peace, on the night of the full moon. He said: "You will surely see your Lord, the Almighty and Majestic, as you see the moon; you will not be crowded in seeing Him. So if you are able to not be overcome regarding these two prayers—before the rising of the sun and before the setting—then do so." Then he recited this verse: {And exalt [Allah] with praise of your Lord before the rising of the sun and before the setting} [Qaf: 39]. Shu'bah said: I do not know if he said "So if you are able" or if he did not say it.