Musnad Abu Ya'la al-Mawsili 154:190

Narrated to us Muhriz ibn 'Awn Abu al-Fadl, narrated to us Malik ibn Anas, from Nafi', from Ibn 'Umar: That the Messenger of Allah (may Allah bless him and grant him peace) forbade *al-shighar*. Malik said: *Al-shighar* is for a man to marry his daughter to another man on the condition that the other man marries his daughter to him.