Musnad Ahmad 30:2539

Abdullah ibn Numayr narrated to us, he said: Ubaydullah narrated to us, from Abu al-Zinad, from al-A’raj, from Abu Hurayrah, who said: "The Messenger of Allah, peace and blessings of Allah be upon him, forbade *al-shighar*." He said: "And *al-shighar* is for a man to say: 'Marry me to your daughter, and I will marry you to my daughter,' or 'Marry me to your sister, and I will marry you to my sister.'" He said: "And he forbade the sale of *al-gharar* (uncertainty), and [the sale by] *al-hasah* (pebble)."