Habib bin Abi Mulaykah (may Allah have mercy on him), whose kunyah was Abu Thawr, said: I was sitting with Sayyiduna Ibn Umar (may Allah be pleased with them both) when a man came to him and asked: Tell me, did Uthman take part in Badr? He said: No. But on the day of Badr the Messenger of Allah (peace and blessings be upon him) said: "O Allah! Uthman is occupied with Your errand and the errand of Your Messenger." So the Messenger of Allah (peace and blessings be upon him) allotted him a share of the spoils as well.
Hadith Referenceالمعجم الكبير للطبراني / العشرة / 124