Muwatta Malik (Yahya)

Imam Malik, may Allah have mercy on him, said that if a person dies and he owes debts to people, each with one witness, and each debt is owed to a different person, each with one witness, and the heirs refuse to take an oath, then the creditors may take an oath and receive their debts. If anything remains, it will not go to the heirs, because by refusing to take an oath, they have relinquished their right. However, if the heirs say that they did not know anything would remain from the debt, and that is why they did not take an oath, and the judge becomes aware that this was indeed the reason the heirs did not take an oath, then in this case, the heirs may take an oath and receive whatever wealth remains.

Hazrat Jameel bin Abdur Rahman used to come to Hazrat Umar bin Abdul Aziz when he would judge among the people. If someone made a claim against another, and if it was apparent that there was association, connection, or relationship between the claimant and the defendant, then he would take an oath from the defendant; otherwise, he would not take an oath.

Imam Malik, may Allah have mercy on him, said: In our view, this is the ruling: if a person makes a claim against another, it will be examined. If the claimant is known to have association and connection with the defendant, then an oath will be taken from the defendant. If he swears an oath, the claim of the claimant will be invalidated. If he refuses, then an oath will be taken from the claimant. If he swears an oath, he will receive his right.