"One cannot expect a Jew who has drifted from the Jewish way of life to transform himself suddenly, and it is necessary to bring him closer to G-d by stages, yet we have to present to him the true aspects of our Torah and Mitzvoth, and not in any diluted form.
Letters by the Lubavitcher Rebbe, p. 176
Seems an obvious point, but how many in kiruv fail to honor it?