Sunan at-Tirmithiy كتاب البيوع باب ما جاء فى كراهية بيع الحيوان بالحيوان نسيئة
The Messenger of God, peace and blessings of God be upon him, said, "The exchange of two animals for one is invalid if delivery is delayed, but is acceptable if the exchange is done on the spot." Click on ḥadīth to read more