The compiler of this book, may Allah سبحانه وتعالى have mercy on him, said: As for Imam عليه السلام statement, peace be upon him, that the judge did not reject it before his emancipation, it means that it was not rejected due to apparent immorality or a condition that undermines his integrity, not because he was a slave, for the testimony of a slave is valid. The first to reject the testimony of a servant was Umar. And as for Imam عليه السلام statement, peace be upon him, that if the slave was freed for the purpose of testimony, his testimony is not valid, it appears to mean that this applies if he testified for his master. However, if he testified for someone other than his master, his testimony is valid whether he was still a slave or had been freed, as long as he was just.
Commentary #2