Musnad Ahmad 30:582

'Abd al-Razzaq narrated to us, Ma'mar informed us, from al-Zuhri, from Ibn al-Musayyib, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "A resident shall not sell for a bedouin, and do not practice najash (bidding up the price without the intention to buy), and a man shall not outbid the sale of his brother, and he shall not propose to a woman to whom his brother has already proposed, and a woman shall not ask for the divorce of her sister (in faith) to empty her vessel."