What is the legal status of a man declaring another man's slave free from his own wealth?

Primary text

If a man tells another man's slave, "You are free from my wealth," this declaration is legally void, and the slave remains a property. If the declarant subsequently purchases the slave, the slave becomes his property without any obligation stemming from the prior declaration. This ruling is held by Malik, Al-Shafi'i, and the majority of jurists.