Power Of Listening

Why is the parsha of Yisro the inroduction to Mattan Torah?  

וישמע יתרו.  Everyone heard, not just Yisro?  The Baalei Mussar distinguish between hearing and listening.  Everyone heard the news, but most didn't listen.  Only Yisro listened and took to heart what the events were saying.

The Gemorah in Bava Kamma (85b) says חרשו נותן לו דמי כולו.  If one makes someone else deaf they don't just pay for the individual's ears but for the individual's full value.  Why must one pay the whole value, why wise it worse than blinding someone if one who is blind is considered dead?  Rav Zilberstein explains that for a person to lose the sense of sight is worse than losing the sense of hearing.  However, damages are assessed according to the value of a servant and for a servant it is more critical that he can hear the masters command.  (Chashukay Chemed Sanhedrin 49b.)  What defines one as an eved is the ability to listen to the master's commands.  The Maharal in Kiddushin (22) says the ears are what make a person a kli kibbul, they make a person into a fashioned, viable human being.  In light of Rav Zilberstein we understand that the essence of an eved is to listen to his master. 

The Beis Halevi asks how could Klal Yisroel accept to fulfill the Torah if they didn't know the details, how could one accept an obligation if they don't know know the extent of it?  He explains that what was accepted at Mattan Torah was not accepting various laws, it was accepting to be the eved of Hashem.  When one accepts to be an eved, they are מקנה themselves to the master and therefore whatever the master says to do, he must do as part of the acceptance of being an eved.  "אבל המוכר עצמו לעבד אינו מקבל עליו שום חיוב רק מקנה גופו לרבו ובזה שפיר חל הקנין, וכיון דהגוף נעשה של הרב הרי ממילא מחויב לעשות כל מה שיאמר הרב וזה פשוט, ומש"ה חל הקבלה על ישראל דהם לא קיבלו על עצמם התורה בגדר חיוב ושיעבוד רק הקנו גופם להתורה ולעבודתו יתברך, וזהו שאמר הכתוב ושמרתם את בריתי דזה קאי על שבע"פ והיא אין לה קצבה וע"כ אמר והייתם לי סגולה מכל העמים, שתהיו קנויים לי ועוסקים בתורה שיהיה לי בכם קנין הגוף לא חיוב גרידא".  

That is why the parsha of Yisro precedes that of Mattan Torah.  Klal Yisroel learnt from Yisro the importance of listening.  To be an eved one must acquire this trait of listening.  Only after they saw such a lesson in practice were they ready to declare themselves עבדים to Hashem and truly listen to what they were told.