Musannaf Ibn Abi Shayba 13:2984

Abu Bakr narrated to us, he said: Waki’ narrated to us, he said: Shu’bah narrated to us, he said: I asked al-Hakam about a man who has a debt owed to him by another man, and he (the debtor) denies it, then some wealth of his (the debtor's) falls into his (the creditor's) possession. Al-Hakam said: Ibrahim said: There is no harm in him taking it, as long as he does not fear that he will be made to swear an oath.