Muhammad bin Suqah (may Allah have mercy on him) says: I was sitting with Ata bin Abi Rabah (may Allah have mercy on him) when a man came and said: "O Abu Muhammad! A man was captured by the Daylam, and they took a promise from him to bring wealth, otherwise he would have to return." He was released, but did not find the wealth. Ata (may Allah have mercy on him) said: "He must fulfill the promise." The man said: "They are polytheists." Ata still ordered him to fulfill the promise.
Hadith Referenceسنن سعید بن منصور / كتاب الجهاد / 3783
Hadith Takhrij«أخرجه سعيد بن منصور فى «سننه» ترقيم الدرالسلفية برقم:، 2606، وعبد الرزاق فى «مصنفه» برقم: 9714، وابن أبى شيبة فى «مصنفه» برقم: 33525»