Someone wrote to the Rebbe King Moshiach Shlita asking how to explain to his fiancé how important it is to cover her hair. After explaining the importance of doing the Mitzvos because G-d says, even if our unlimited minds do not understand His reasons, and the great reward for covering hair as stated in the Zohar, the Rebbe King Moshiach Shlita says that one can succeed by influencing a person indirectly through friends, and persisting tirelessly in pleasant and peaceful ways. In addition:
...in the majority of cases, when one sees that one is not succeeding in influencing another in matters of Torah and Mitzvos, there is an internal obstacle – that the influencer is lenient in matters of Torah and Mitzvos, albeit in different Mitzvos (than the ones he is trying to influence another to keep), and automatically one is repaid with lack of success in his words of inspiration, for G-d repays measure for measure. All the Mitzvos are interconnected...248 positive Mitzvos corresponding to the 248 limbs of a person and 365 negative Mitzvos corresponding to the 365 sinews, and all the limbs and sinews are one united body. When he will improve in what needs correction in his own matters, he will certainly have improved success in influencing his fiancé...
(See letter of the Lubavitcher Rebbe King Moshiach Shlita, Igros Kodesh vol. 13, pg. 102-103)
