Mitzvos As Path To Love
וכתי' לאהבה את ה' כו' פירש"י של"ת אלמוד בשביל שאקבל שכר כו'
And it is written, "to love Hashem..." (Devarim 11:13); Rashi explains that one should not say, "I will learn in order to receive reward..."
The verse commands us to love Hashem, and Rashi warns against serving Him merely to collect reward.
פי' להיות תשמעו א"מ כדי לאהבה את ה' ולעבדו כו' שזה התכלית מהמצות שהם עיטין איך למפלח בדו"ח
The meaning is that the result of "if you will surely listen" is to love Hashem and to serve Him, for this is the very purpose of the mitzvos, which are counsel and guidance for how to serve Him with awe and love.
The whole point of the mitzvos is not the reward but that they are the practical means to reach love and service of Hashem with awe and love.
וזהו א"ש תשמעו ב"פ
And this is what is alluded to in the doubled expression of "listen" (shamo'a tishme'u).
The Torah doubles the word "listen" to hint at two distinct goals embedded in that listening.
שמיעת מ"ע עצה לבוא לאהבה
The listening to the positive commandments (mitzvos asei) is counsel to come to love.
Heeding the positive mitzvos is the avenue through which a person arrives at love of Hashem.
ושמיעת מל"ת לבוא לעבדו בכל לב ונפש
And the listening to the prohibitions (mitzvos lo sa'aseh) is counsel to come to serve Him with all one's heart and soul.
Heeding the prohibitions is the avenue through which a person comes to serve Hashem with his entire heart and soul.
ולכן שמוע תשמעו לקבל ולהאזין הארת המצות בכל אבר להיות בטל כל אבר להמצוה שהוא פנימיות האברים וגידין
Therefore, "you shall surely listen" — to receive and to incline one's ear to the illumination of the mitzvos in every limb, so that every limb should become utterly nullified (bittul) to the mitzvah, which is the innermost essence of the limbs and the sinews.
Truly listening means absorbing the light of the mitzvos into every limb, until each limb is wholly nullified to the mitzvah, which is the inner core animating the body.
והוא כמ"ש שמעי בת כו' ואח"כ הטי אזנך להיות נמשך לגמרי אחר המצוה:
And this is as it is written, "Listen, O daughter..." (Tehillim 45:11), and afterward, "and incline your ear," so that one should be drawn entirely after the mitzvah.
Dovid HaMelech first says "listen" and then "incline your ear," teaching a progression in which a person is ultimately drawn completely after the mitzvah.
Summary: The Sfas Emes explains that the doubled command "shamo'a tishme'u" (if you will surely listen) points to the true purpose of the mitzvos: not the collection of reward, as Rashi warns, but reaching love and service of Hashem. The mitzvos are the practical counsel for how to serve the Ribono shel Olam with awe and love. The positive mitzvos are the path to love of Hashem, while the prohibitions are the path to serving Him with all one's heart and soul. True listening draws the illumination of the mitzvos into every limb until each limb is utterly nullified to the mitzvah, which is the innermost essence of the body. This mirrors the progression in Tehillim of first "listening" and then "inclining one's ear," until a person is drawn entirely after the mitzvah.