Sayyiduna Salman al-Farisi (may Allah be pleased with him) said: I gathered firewood and prepared some food, then brought it to the Prophet (peace and blessings be upon him); it was only a little. I placed it before him (peace and blessings be upon him), and he asked: "What is this?" I said: It is charity (sadaqah). He (peace and blessings be upon him) said to his Companions: "Eat," and he himself did not eat. I said (to myself): This is one of his signs. Then I stayed as long as Allah willed, then I said to my mistress: Grant me a day off. She said: Very well. So I went and gathered firewood and sold it for more than before, and prepared food, then brought it to the Prophet (peace and blessings be upon him) while he was among his Companions. I placed it before him, and he asked: "What is this?" I said: It is a gift. He (peace and blessings be upon him) reached out his hand (to the food) and said to his Companions: "Eat with the name of Allah." I said: I bear witness that you are the Messenger of Allah. He asked: "How so?" So I told him about the man (who had told me of his signs), then I said: O Messenger of Allah! Will he enter Paradise? For he told me that you are a Prophet. He (peace and blessings be upon him) said: "None will enter Paradise except a Muslim soul."
Hadith Referenceالمعجم الكبير للطبراني / باب السين / 6130