It is narrated from Hazrat Abu Hurairah (may Allah be pleased with him) that no one knows more of the sayings of the Holy Prophet (peace and blessings be upon him) than me except Abdullah bin Amr (may Allah be pleased with him), because he used to write them down with his hand and preserve them in his heart, whereas I only preserved them in my heart and did not write them down with my hand. He had sought permission from the Holy Prophet (peace and blessings be upon him) to write, which the Holy Prophet (peace and blessings be upon him) granted him.