Nasij al-Hadrami (may Allah have mercy on him) says: The Prophet (peace and blessings be upon him) passed by two men who were swearing oaths to each other over a sale. One was saying: By Allah! I will not lower (the price), and the other was saying: I will not increase it. Then he (peace and blessings be upon him) saw a goat that he had bought, and he (peace and blessings be upon him) said: "You have made one of two things binding, that is, sin and expiation."
Hariz bin Uthman alone narrated it with this chain, and Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الأيمان / 19866