Sayyiduna Abu Hurayrah (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him) said: "The pledged item is not to be withheld from the one who pledged it; its benefit and gain are his, and its loss is his."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الرهن / 11219