Jesus' plan called for action, and how He expressed it predicted its success. He didn't say "you 'might' be my witnesses," or "you 'could' be my witnesses," or even "you 'should' be my witnesses. " He said "you 'WILL' be my witnesses.
Upon the present occasion London was full of clergymen. The specially clerical clubs, the Oxford and Cambridge, the Old University, and the Athenaeum, were black with them.