Preet Bharara, who was fired in March from his post as U.S. attorney for the Southern District after he refused to resign at President Donald Trump’s behest, encouraged New York Law School graduates during a commencement address on Thursday to question others—even their superiors—when the time is right.

“Justice cannot tolerate fake news, or alternative facts or abuse of power,” said Bharara, himself a Columbia Law School graduate, at New York Law School’s graduation ceremony at Lincoln Center, where he was presented with an honorary degree.