Musnad Abu Ya'la al-Mawsili 36:1

Amr ibn Muhammad al-Naqid narrated to us, Waki' narrated to us, Yahya ibn Abd al-Rahman ibn Abi Labibah narrated to us, from his grandfather, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Whoever deems lawful [a marriage] with a dirham in marriage, he has deemed lawful [the private parts]."