Another way of saying no sign will be given?

I think this illustrates perfectly the whole concept of no additional sign will be given.  Jesus is basically saying "Look, you have God's Word in the Bible and if you aren't going to believe that then you aren't going to believe anything else. " 

Either take God at His word or call Him a liar if you dare but He isn't going to offer additional proof just to try and convince you to believe Him.

Luke 16:27-31(NKJV)

“Then he said, ‘I beg you therefore, father, that you would send him to my father’s house, 

for I have five brothers, that he may testify to them, lest they also come to this place of torment.’ 

Abraham said to him, ‘They have Moses and the prophets; let them hear them.’ 

And he said, ‘No, father Abraham; but if one goes to them from the dead, they will repent.’ 

But he said to him, ‘If they do not hear Moses and the prophets, neither will they be persuaded though one rise from the dead.’”