The Rebbe has a Maamar on Parshas Shelach that compares and contrasts the spies sent by Moshe and Yehoshua in the Parsha and Haftarah respectively. Looking at the Parsha through the Lens of Chassidus, we are presented with a clear and direct way to implement the parsha’s message into our life. The Rebbe explains that the spies of Yehoshua are relevant to each and every Jew while the Spies sent by Moshe are more relevant if not entirely to the service of the Tzaddik. In short, the Spies sent by Yehoshua went to Jericho which is called the lock of the land and represents are persons thought, speech, and action. A person is able to conquer these aspects of their life and when they are successful then the entire land which represents the 7 emotional attributes of a person is exposed to be conquered.
When a person thinks about something, and this generates speech in which to express the idea, it seems that if action doesnt come because of it, then its best not to say anything at all.