Musnad Ahmad 831:1

'Abd al-Razzaq narrated to us, Ibn Jurayj and Ibn Bakr narrated to us, Ibn Jurayj informed us, and Abu 'Asim, from Ibn Jurayj, Isma'il ibn Muhammad ibn Sa'd informed me that Humayd ibn 'Abd al-Rahman ibn 'Awf informed him that al-Sa'ib ibn Yazid informed him that he heard al-'Ala' ibn al-Hadrami saying: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The Muhajir (emigrant) shall remain in Makkah after the completion of his rites for three [days]." Abu 'Asim said: "Three nights."