Musnad Ahmad 790:131

Ibrahim ibn Ishaq al-Taliqani narrated to us, al-Harith ibn Umayr narrated to us, from Humayd al-Tawil, from al-Hasan, from Imran ibn Husayn, that the Prophet, peace and blessings of Allah be upon him, said: "There is no *jalab* (bringing horses or camels to a race and driving them from behind), no *janab* (the person who stands aside to urge the horses on), and no *shighar* (a type of marriage where a man gives his daughter in marriage to another on the condition that the other gives his daughter to him) in Islam. And whoever plunders, he is not from us."