Abu Dawud Book 19, Hadith Number 3658.
Narated By Abu Sa’id al-Khudri : I was sitting in the company of the poor members of the emigrants. Some of them were sitting together because of lack of clothing while a reader was reciting to us. All of a sudden the Apostle of Allah (PBUH) came along and stood beside us. When the Apostle of Allah (PBUH) stood, the reader stopped and greeted him.
He asked: What were you doing? We said: Apostle of Allah! We had a reader who was reciting to us and we were listening to the Book of Allah, the Exalted.
The Apostle of Allah (PBUH) then said: Praise be to Allah Who has put among my people those with whom I have been ordered to stay. The Apostle of Allah (PBUH) then sat among us so as to be like one of us, and when he had made a sign with his hand they sat in a circle with their faces turned towards him.
The narrator said: I think that the Apostle of Allah (PBUH) did not recognize any of them except me.
The Apostle of Allah (PBUH) then said: Rejoice, you group of poor emigrants, in the announcement that you will have perfect light on the Day of Resurrection. You will enter Paradise half a day before the rich, and that is five hundred years.