Musnad Abu Ya'la al-Mawsili 153:179

Sufyan ibn Waki' narrated to us, Ishaq ibn Mansur al-Asadi narrated to us, from Asim ibn Muhammad, from Waqid, from his father, from Ibn Umar, from the Prophet (peace and blessings of Allah be upon him), who said: "How will you be, O Abdullah ibn Umar, when you remain among the dregs of the people, whose covenants and trusts have become disordered, and they have differed and become like this?" And he interlaced his fingers. He said: "So what should I do, O Messenger of Allah?" He said: "Take what you recognize, leave what you reject, attend to your own private affairs, and leave their common folk."