Musannaf Ibn Abi Shayba 13:2621

Abu Bakr narrated to us, he said: Isma'il ibn 'Ulayyah narrated to us, from Hisham al-Dastawa'i, he said: Hammad narrated to us, from Ibrahim, he said: The compensation (ghurm) is from the wealth of the seller, because he was the first of the two to break the oath.