It is unlawful for any person knowingly or wilfully to resist, oppose or obstruct any law enforcement personnel, the city judge, or any other officer or employee of the city in the discharge of his official duties; or, by threats or otherwise, to intimidate or attempt to intimidate any officer or employee from the discharge of his official duties; or to assault or beat, or revile, abuse, be disrespectful to, use abusive or indecent language toward or about any officer or employee while the officer or employee is in the discharge of his official duties. (2001 Code § 134.02)