(21) باب بَيْعَةِ الْمَمَالِيكِ
It was narrated that jabir said:
"A slave came and pledged to the Prophet to emigrate, and the Prophet did not realize that he was a slave. Then his master came looking for him. The Prophet said: 'Sell him to me,' and he bought him for two black slaves. Then he did not accept the pledge from anyone until he asked: 'Is he a slave?"'
Reference: Sunan an-Nasa'i 4184
In-book reference: Book 39, Hadith 36
English translation: Vol. 5, Book 39, Hadith 4189