After Yaakov succeeded in obtaining the brachos that Yitzchok had intended for Eisav, Eisav planned his revenge. The Torah tells us, "When Rivkah was told the words of Eisav she called her younger son Yaakov and told him, 'Eisav intends to kill you'" (Bereishis 27, 42). Rashi explains that Rivkah was informed of this information through ruach hakodesh. Nevertheless, notes Rav Wolbe (Shiurei Chumash), when Rivkah wished to send Yaakov to safer pastures, she told Yitzchok that the reason for her decision to send him off was because it was time for him to get married, and she was disgusted by the local prospective wives. She made no mention about the spiritual revelation that was the real impetus for her actions.
From this incident, we can perceive the amazing quality of tznius that characterized Rivkah's actions. She attained a level of spirituality that most people in the history of the world could only wish for, and she didn't let anyone in on the secret - even Yitzchok. Additionally, from this story we can deduce another trait that is attributed to great people. Though the real reason for her sending off Yaakov was for his own safety, she gave a totally different reason to Yitzchok.
Rav Wolbe continues, that many times gedolim mention one reason for a specific decision, while there are really more factors that contributed to the decision. Moreover, it may very well be that they didn't mention the main reason for their coming to their conclusion. There are people who for one reason or another decide that the reason given by the gedolim doesn't strike their fancy or simply does not apply to them. However, had they known everything behind the remarks of the gadol, they would not be so quick to act differently. This is one of the reasons that we have a concept called emunas chachomim. We act in accordance to what our gedolim tell us, regardless of whether we understand the reason or not.
A talmid once asked Rav Yeruchom Levovitz for permission to leave Yeshiva to travel somewhere. Being that it was Wednesday, Rav Yeruchom told him that there is a principle that one is not supposed to start something new on Monday or Wednesday. However, at a later date, Rav Yeruchom was giving a Chumash shiur and mentioned that the above concept does not apply to traveling. Rav Wolbe deduced from this incident, that the explanation Rav Yeruchom gave the talmid who requested permission was not the true reason for his decision. Either he didn't wish to reveal the true motive, or he was concerned that the bachur was planning on traveling regardless. Since he did not want the talmid to be guilty of defying his Rebbi, he gave him a reason that had no personal rationale.