Musannaf Ibn Abi Shayba 9:664

Abu Bakr narrated to us, from Isma'il ibn 'Ayyash, from Ibn Jurayj, from 'Ata, from Ibn 'Abbas, regarding a man who married a woman, and they stipulated to him: "If you bring her dowry by such and such [time], and if not, then there is no marriage between us." Ibn 'Abbas said: "There is no harm in that."