It is narrated from Sayyiduna Wathilah bin al-Asqa' (may Allah be pleased with him); he said: the Messenger of Allah (peace and blessings be upon him) used to come out to us, and we were merchants, and he would say: "O community of merchants, beware of lying."
Hadith Referenceالمعجم الكبير للطبراني / باب الواو / 18352