1. If the Chassid had spoken out the plan to fix the fence, he would be in violation of speaking (forbidden). Nevertheless, during the week he would be able to fix the fence (permitted). Thus, if - having spoken - he did not fix the fence it would be a chumra.
2. If so, then why is it considered meritable that having thought of fixing the fence (permitted) he refrained from doing so (permitted).
I.e. he did something permissible, and then he refrained from performing an act that would have been permissible, even if he had violated the prohibition?
How do you explain that his actions were meritable? Who says that under any circumstances - even if speaking - one is to refrain from performing the act one spoke about?
Does there exist any source that relates SPEAKING about an issur, to refraining from performing the act one spoke about during the week?
Elan , Los Angeles, California, US
1. I see that you understand that the Chasid was Machmir in the Isur of saying on Shabbos that he will do an act that is forbidden.
The Taz (OC 307:14) offers two possible explanations for the Chumrah of the Chasid. Firstly, he was Machmir on himself to consider Machshavah k'Ma'aseh. He explains that the Chasid had originally planned to ask a gentile to build the fence, but realised that this is forbidden (Shvus of Amirah l'Nochri) and refrained from doing so, but was stringent with himself as if he has indeed asked the gentile to work for him. The Taz says that this is a proof for those opinions that if a gentile does work for a Jew on Shabbos the Jew may never benefit from that work. According to this explanation it was a Chumrah on the law of Amirah l'Nochri.
Alternatively he suggests that the Chasid had considered on Shabbos how he may best build a fence after Shabbos. He subsequently decided that this was not a correct thing to do on Shabbos and decided not to benefit from this thought by building the fence he had wrongly thought about on Shabbos. The Taz does not specify why this thought was forbidden. Perhaps he means to say it is included in the Mitzvah that one should not consider one's business needs on Shabbos (OC 306:8). This also appears to be the opinion of the Meiri and Aruch ha'Shulchan (306:1).
2. I am not aware of any source for the idea you suggest.
Dov Freedman