Malik related to me from Hisham ibn Urwa from his father thatA'isha, the wife of the Prophet, may Allah bless him and grant himpeace, said, "Barira came to me and said, 'I have written myself asmukatab for my people for nine uqiyas, one uqiya per year, so helpme.' A'isha said, 'If your people agree that I pay it all to them foryou, and that if I pay it, your wala' is mine, then I will do it.'Barira went to her masters and told them that and they didn't agree.She came back from her masters while the Messenger of Allah, may Allahbless him and grant him peace, was sitting. She said to A'isha, 'Ioffered that to them and they refused me unless they had the wala'.'The Messenger of Allah, may Allah bless him and grant him peace, heardthat and asked her about it A'isha told him and the Messenger ofAllah, may Allah bless him and grant him peace, said, 'Take her andstipulate that the wala' is yours, for the wala' is for the one whosets free.' So A'isha did that and then the Messenger of Allah, mayAllah bless him and grant him peace, stood up in front of the people,and praised Allah and gave thanks to Him. Then he said, 'What is wrongwith the people who make conditions which are not in the Book ofAllah? Any condition which is not in the Book of Allah is invalid evenif it is a hundred conditions. The decree of Allah is truer and theconditions of Allah are firmer, and the wala' only belongs to the onewho sets free.' "
USC-MSA web (English) reference: Book 38, Hadith 17
Arabic reference: Book 38, Hadith 1482