Ash-Shama'il Al-Muhammadiyah, Book 48, Hadith 353 (In-Book)

Ibn 'Abbaas Radiyallahu 'Anhu says: "Rasulullah Sallallahu 'Alayhi Wasallam was the most generous among people in performing good deeds (No one could compare with him in generosity. He himself led a simple life, but in giving he would put a king to shame. At a time of great need a woman presented him a sheet, and he wore it as he was in need of it. A person came to him, and asked him for it, he presented the sheet to that person. Taking of loans and fulfilling the needs of others, when the creditors came, and if something had come from somewhere, he would pay the debts, and did not go home till everything was given to the needy. There exists many incidents of this nature, so much so that it is not possible to enumerate them). Particularly in the month of Ramadaan, he would be more generous till the month ended. (His generosity in this month exceeded all the other months). In this month when Jibra-eel 'Alayhis Salaam came and recited the Qur-aan to Rasulullah Sallallahu 'Alayhi Wasallam, at that time his generosity exceeded the wind that brings forth heavy rains".

حَدَّثَنَا عَبْدُ اللهِ بْنُ عِمْرَانَ أَبُو الْقَاسِمِ الْقُرَشِيُّ الْمَكِّيُّ، قَالَ‏:‏ حَدَّثَنَا إِبْرَاهِيمُ بْنُ سَعْدٍ، عَنِ ابْنِ شِهَابٍ، عَنْ عُبَيْدِ اللهِ، عَنِ ابْنِ عَبَّاسٍ، قَالَ‏:‏ كَانَ رَسُولُ اللهِ صلى الله عليه وسلم، أَجْوَدَ النَّاسِ بِالْخَيْرِ، وَكَانَ أَجْوَدَ مَا يَكُونُ فِي شَهْرِ رَمَضَانَ، حَتَّى يَنْسَلِخَ، فَيَأْتِيهِ جِبْرِيلُ، فَيَعْرِضُ عَلَيْهِ الْقُرْآنَ، فَإِذَا لَقِيَهُ جِبْرِيلُ كَانَ رَسُولُ اللهِ صلى الله عليه وسلم، أَجْوَدَ بِالْخَيْرِ مِنَ الرِّيحِ الْمُرْسَلَةِ‏.‏

also referenced under: Book 47, Hadith 336 (English)