Musnad Ahmad 1119:33

Bahz narrated to us, he said: Abu 'Awanah narrated to us, he said: Qatadah narrated to us, from Abu al-Malih, from 'Awf ibn Malik al-Ashja'i, who said: The Messenger of Allah (ﷺ) camped with us one night, and each man among us spread out the forearm of his riding beast. He said: I went toward some of the camels, and there was the she-camel of the Messenger of Allah (ﷺ), with no one in front of it. He said: So I set out seeking the Messenger of Allah (ﷺ), and there were Mu'adh ibn Jabal and 'Abdullah ibn Qays standing. I said: "Where is the Messenger of Allah?" They said: "We do not know, except that we heard a sound at the top of the valley, like the humming of a millstone." He said: "Wait a little." Then the Messenger of Allah (ﷺ) came to us and said: "Indeed, one came to me tonight from my Lord and gave me the choice between having half of my nation enter Paradise or [having] the intercession, and I chose the intercession." We said: "We adjure you by Allah and by [our] companionship, make us among the people of your intercession." He said: "You are indeed among the people of my intercession." He said: So we came toward the people at a fast pace, and they were alarmed, having missed their Prophet. The Messenger of Allah (ﷺ) said: "Indeed, one came to me tonight from my Lord and gave me the choice between having half of my nation enter Paradise or [having] the intercession, and I have chosen the intercession." They said: "O Messenger of Allah, we adjure you by Allah and by [our] companionship, make us among the people of your intercession." He said: When they pressed upon him, he said: "Then I call you to witness that my intercession is for whoever among my nation does not associate anything with Allah."