Musannaf Ibn Abi Shayba 28:1049

Ali ibn Mushir narrated to us, from Abd al-Rahman ibn Ishaq, from al-Nu'man ibn Sa'd, who said: I heard al-Mughira ibn Shu'ba saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The slogan of the Muslims on the Day of Resurrection, upon the Sirat (the bridge), is: 'O Allah, grant safety, grant safety.'"