Zayd bin Aslam reported,

In the days of before Islam, riba worked like this. A man would owe another man a debt due on a set date, and when the date arrived the creditor would ask, "Will you pay, or will you increase it?" If the debtor paid, the creditor took what was owed. If not, the creditor added to the amount owed and extended the due date for him.

و حدثني مالك

عن زيد بن أسلم أنه قال

كان الربا في الجاهلية أن يكون للرجل على الرجل الحق إلى أجل فإذا حل الأجل قال أتقضي أم تربي فإن قضى أخذ وإلا زاده في حقه وأخر عنه في الأجل