Sayyiduna Ibn Abbas (may Allah be pleased with them both) said about the verse "It is not for a prophet to act dishonestly (with the spoils)" [Surah Al Imran: 161]: "It is about a red velvet sheet that went missing on the day of Badr. People said: He (the Messenger of Allah, peace and blessings be upon him) has taken it. So this verse was revealed: 'It is not for a prophet to act dishonestly (with the spoils).'"
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 11977