'Three Days' in the Bible

And the king saith unto Amasa, 'Call for me the men of Judah in three days, and thou, stand here,'

And Gad cometh in unto David, and declareth to him, and saith to him, 'Do seven years of famine come in to thee in thy land? or three months art thou fleeing before thine adversary -- and he pursuing thee? or are three days' pestilence in thy land? now, know and see what word I take back to Him sending me.'