Musnad Ahmad 5:763

'Abdullah narrated to us, Suwayd ibn Sa'id narrated to me, 'Ali ibn Mushir informed us, from 'Abd al-Rahman ibn Ishaq, al-Nu'man ibn Sa'd narrated to us, he said: We were sitting with 'Ali, may Allah be pleased with him, and he recited this verse: "The Day We will gather the righteous to the Most Merciful as a delegation" [Maryam: 85]. He said: "No, by Allah, they will not be gathered on their feet, and the delegation is not gathered on their feet. Rather, [they will be] upon she-camels, the likes of which the creatures have never seen, upon them are saddles of gold, so they will ride upon them until they strike the gates of Paradise."