Musnad Ahmad 27:1217

Abu al-Nadr narrated to us, Abd al-Rahman ibn Thabit ibn Thawban narrated to us, Hassan ibn Atiyyah narrated to us, from Abu Munib al-Jurashi, from Ibn Umar, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "I was sent before the Hour with the sword, until Allah alone is worshipped, with no partner for Him. My provision was placed under the shadow of my spear, and humiliation and lowliness were placed upon those who oppose my command. And whoever imitates a people, he is one of them."