There shall no sign be, &c. = lf there shall be a sign given, &c. A Hebrew idiom; = ye will see a sign; but the sentence is left unfinished by the Figure of speech Aposiopesis (App-6). The word "if" implies that there is no doubt about it. See App-118. Compare Gen_21:23. Deu_1:35. 1Ki_1:51.