Musannaf Ibn Abi Shayba 13:2525

Abu Bakr narrated to us, he said: Abd al-Wahhab al-Thaqafi narrated to us, from Ayyub, from Abu Qilabah, from Abu al-Ash'ath, who said: We were on a military expedition and Mu'awiyah was over us. We obtained silver and gold, and Mu'awiyah ordered a man to sell it to the people in exchange for their stipends. The people rushed toward it, so 'Ubadah stood up and forbade them, and they returned it. The man came to Mu'awiyah and complained to him. Mu'awiyah stood up as a preacher and said: "What is the matter with men who narrate hadiths from the Messenger of Allah (may Allah bless him and grant him peace) in which they lie about him, which we did not hear?" 'Ubadah stood up and said: "By Allah, we will certainly narrate from the Messenger of Allah (may Allah bless him and grant him peace), even if Mu'awiyah dislikes it. The Messenger of Allah (may Allah bless him and grant him peace) said: 'Do not sell gold for gold, nor silver for silver, nor wheat for wheat, nor barley for barley, nor dates for dates, nor salt for salt, except like for like, equal for equal, hand to hand.'"