Someone once concluded a letter to the Rebbe saying that, in
essence, he is a Jew who wants to fulfill the Mitzvos of the Torah, yet, he is
not [yet] religious and does not keep Shabbos, etc.
The Rebbe addressed this apparent dichotomy in his response:
As it is with one’s physical life, talking about the benefits of food, and even
having a strong belief in its importance, is to no benefit. One has to actually
eat the food. Furthermore, if one does not actually
eat food, he will become so weak that he won’t even have strength to talk about it...
So too, with regard to spiritual “food”. One can talk about
and have strong beliefs about the importance of Mitvos, and may even espouse to
have a strong desire to fulfill them; nevertheless, the Neshama will not be nourished
from talk and belief alone. One has to actually do the Mitzvos.
המעשה הוא העיקר
Igros Kodesh Vol 9 – Rosh Chodesh Elul 5714