What is a defendant's duty to act with reasonable diligence?

It was the duty of the appellants (plaintiffs) to act and to act with reasonable diligence. They are the ones who started the proceedings in motion, and they had the power and duty to pursue all the necessary steps to bring the litigation to an end. Upon the respondent (defendant) is the duty to make response to the movements of the appellant. It is no answer to say that a defendant did not utter a word of protest against the delay or that the court did not call plaintiff to his task of proceeding. (Cohn v. Rosenberg, supra, 62 Cal.App.2d 140, 145, 146, 144 P.2d 399.)