Is it permissible to refrain from testifying in a case if it would result in personal harm, in accordance with the principle that "averting harm takes precedence over acquiring benefits"?

"Rendering testimony concerning the rights of individuals is a communal obligation (fard kifaya). It may become an individual obligation (fard ayn) if the right depends on his testimony and no one else is available. For the obligation to render testimony to be incumbent, it is stipulated that it should not result in harm to the witness in his body, property, family, or honor. However, if the witness is harmed by what he will testify to, this does not negate the obligation to render testimony; rather, he must speak the truth, even if it is against himself."