Musnad Ahmad 30:2702

Hajjaj narrated to us, he said: Layth narrated to us, he said: Bukayr ibn Abdullah narrated to me, from Nu’aym Abu Abdullah al-Mujmir, that he said: I prayed with Abu Hurayrah above this mosque, and he recited "When the sky has split [Idha al-sama'u inshaqqat]," and he prostrated during it. And he said: "I saw the Messenger of Allah, may Allah bless him and grant him peace, prostrate during it."