Here is the quote from Ibn Ishaq's "Sirat Rasulallah", translated as "The Life of Muhammad", by A. Guillaume, (page 496):
"So the apostle called Burayra (Aisha's slave) to ask her, and Ali got up and gave her a violent beating saying, "Tell the apostle the truth,"....
Muhammad did not stop Ali from beating the slave.
According to the Quran slaves should be treated nicely. So is the narration from Ibn Ishaqs account true?
Please Answer