Musnad Ahmad 27:1403

'Affan narrated to us, Shu'bah narrated to us, from 'Abdullah ibn Dinar, from Ibn 'Umar, that a man from Quraysh said to the Messenger of Allah, may Allah bless him and grant him peace: "I buy and sell, and I am deceived." He said: "When that happens, say: 'No deception (la khilabah).'"