In life, nothing is as simple as a mere five word statement. Let us analyze the statement. Supposing you could save the life of an innocent child ("the end") and you could do it by lying ("the means") about his whereabouts to the murderer. In such a case Judaism would definitely say that the end justifies the means. However, supposing I could convince someone of the truth of the Torah ("the end") by lying ("the means") about what Torah is, then the Torah would say that it is not justified. Because here the means are a direct contradiction to the end, which is truth. We believe that one should examine each case separately, and indeed Judaism has legal guidelines to teach us how to act in cases of end versus means.
