It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he (peace and blessings be upon him) said: "Do not inflate prices (by fake bidding), a town-dweller should not sell for a desert-dweller, a man should not sell over the sale of his brother, nor should he propose over his proposal, and a woman should not ask for her sister's divorce so as to empty what is in her vessel."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10890