I had heard that the reason the Chasid considered the thought so wrong that he never fixed the fence is because the menuchas Shabbos is supposed to be "ke'ilu kol melachtecha asuya" and is a reflection of "Vaychal Elokim etc."

Therefore, even thinking that something was missing from his gashmi world was a setira to this concept and needed to be rectified by showing that it was not really missing and he could live without that melacha.

I saw the following in the Daf Digest from the Chicago Center for Torah and Chessed:

Thinking About Weekday Matters on Shabbos

_Although the Gemara (150a) rules that it is permitted to think of weekday matters on Shabbos, it subsequently (150b) cites the episode of a certain very pious individual who found himself thinking of his weekday matters on Shabbos and felt that he had thereby violated the sanctity of Shabbos.

Reb Tzadok HaKohen of Lublin (Yisrael Kedoshim #8) writes that when we thank Hash-m in the Minchah of Shabbos for providing us with the potential to achieve a Menuchas Emes Ve'emuna­ a rest of truth and belief - we are referring to our potential to attain the level of that very pious individual. For the ideal Menuchas Shabbos in which even in the depth of our hearts we regard all weekday matters as having been completed and no longer requiring our attention.

It does not suffice for us to do the minimum, to refrain from forbidden activities yet at the same time allow our hearts to continue being distracted by our commerce and craft. Only such a state can rightly be termed a Menuchas Emes, for truth is that which penetrates to our greatest depths and remains consistent. A "truth" that only "holds true" on a superficial level (refraining from expressing concern over weekday matters, yet at the same time considering, these matters in our mind) cannot be called "true." Such superficial truth might fool other people, but not Hash-m, concerning whom it is said Chosamo Emes ­ his seal is truth.

Thus, while refraining from mundane conversation is a technical fulfillment of the command to desist from expressing oneself in weekday matters, it is not a Menuchah Sheleimah (a truly complete, befiting rest).

Hence, concludes Reb Tzadok, those who are in awe of G-d because they are cognizant of Hash-m's knowledge of that which is concealed deep in one's heart are extremely meticulous and vigilant in barring any weekday thoughts from their minds.

Gershon

gershon.dubin@juno.com