Musnad Ahmad 120:1

Abu al-Nadr narrated to us, Muhammad ibn Abdullah al-Umari narrated to us, Abu Sahl Awf ibn Abi Jamilah narrated to us, from Zayd Abu al-Qamus, from the delegation of Abd al-Qays, that they heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "O Allah, make us among Your chosen servants, the ones with bright foreheads and limbs, the accepted delegation." He said: So they said, "O Messenger of Allah, who are the chosen servants of Allah?" He said: "The righteous servants of Allah." They said: "And what are the ones with bright foreheads and limbs?" He said: "Those whose places of ablution will be bright." They said: "And what is the accepted delegation?" He said: "A delegation that will arrive from this nation with their Prophet to their Lord, Blessed and Exalted is He."