Or istishab in Arabic; it is a doctrine of Islamic law (shari’a), and a secondary source of shari’a, which refers to the application of a previous ruling (hukm) as long as no other contradictory or negating evidence is available from a definitive main source (Qur’an or Sunnah). For instance, if a person claims he lent another an amount of money, and demands repayment. But there is no material proof of this debt. Istishab (spelled istis-hab) will consider the other person free from debt as there is no tangible proof of his liability in the first place.