"At that time Hashem separated out the tribe of Levi to bear the Ark of the Covenant, to stand before Hashem, to minister unto Him, and to bless His name even until today. Therefore Levi has no portion in the inheritance of his brothers; Hashem is his inheritance as Hashem your G-d spoke to him." (Deut. 10:8-9)
Why didn't the tribe of Levi (including Cohen) get any inheritance?
The Rambam, in the very end of the Laws of the Sabbatical and Jubilee years, (Chapter 13:12) writes a beautiful reason. Levi, since they were dedicated to the service of Hashem, were removed from the regular constraints of worldly existence. They didn't have to earn a living. They were to devote themselves exclusively to Hashem's service and He provided for them, as it written, "May Hashem bless his wealth . . ." (Deut. 33:11) And Hashem takes care of them as it is written, "I will be your portion and your inheritance. . ." (Num. 18:20)
Then the Rambam continues (Chapter 13:13) to explain that this arrangement is not applicable to Levi alone. Any person, who wants to dedicate himself totally to the service of Hashem and His Torah, to become devoted to Him and to know His ways, must begin by severing himself from all worldly pursuits. He then becomes consecrated; Holy to Hashem. For him Hashem will provide, just as He provided for the Cohanim and Leviim. As is written, "Hashem is my portion and my s hare, He guides my destiny." (Psalms 16:5) This is the meaning of the Mishna in Ethics of the Fathers (3:6), "Rebbe Nachunya ben Hakana said, "When one accepts upon himself the yoke of Torah, he becomes exempt from the yoke of military service and the yoke of making a living. When one throws off the yoke of Torah, the yoke of military service and the yoke of making a living are imposed upon him.'"
The Rambam reiterates the same idea in his commentary on the Ethics of the Fathers. (4:17) He explains the 3 crowns; the Crown of the Kahuna (priesthood), the Crown of Malchus (kingship), and the Crown of Torah. The Crown of Kahuna belongs to Aharon and his descendants, the Crown of Malchus belongs to David and his descendants. The Crown of Torah is different. The Crown of Torah awaits anybody who will come and put it on.
Another incredible thought from my friend Rabbi Novick at Tel Aviv University:
"And now Israel, what does the L-rd your G-d ask of you; only to fear (yirah) the L-rd your G-d, to walk in all His ways and to love Him, to work for the L-rd your G-d, with all of your heart and all of your soul." (Devarim 10:12)
The concept of "yirah" is often difficult for Western modern man to relate to, and the common English translation, "fear", does not promote understanding. On the deepest level, "yirah" is rooted in loving-kindness. One needs to contemplate that the principle pleasure and desire of the Creator, is only to bestow unlimited loving-kindness on the Creation.
Creation took place so that this loving-kindness would be recognized and received in the world. We are vessels that consciously control the quality and quantity of what we receive. G-d, from His side, is constantly pouring out the maximum amount of loving-kindness. Man, through his actions can prevent the G-dly flow of loving-kindness to the world, consequently impeding the completion of Creation's purpose.
The arousal that follows this realization that your actions can inhibit G-d's desire and pleasure is called "yirah".
"If you are careful to heed my commandments which I am commanding to you today to love the Lord your G-d, to serve Him with all your heart and with all your soul, then . . . " (Devarim 11:13) (This is in the text of the second Parsha in the Shema.)
Commenting on the words, ". . . to love the Lord your G-d, to serve Him with all your heart . . ", Rashi zt"l says, ". . . this is the service of the heart; it is prayer." (Tefilah)
The Yismach Moshe, Rabbi Moshe Teitlebaum of Uhely asks a penetrating question. Why is prayer called the service of the heart?
1) Why is prayer called the service of the heart more than any
of the other types of "heartful" ways of service such
as love and fear?
The answer is found in the root of the word for prayer itself; Tefilah. Tefilah means joining or connecting. (see the comment of Rashi on Bereishis 30:8 concerning the naming of Naftali) Tefilah requires the mouth, not just the meditations of the heart. Service is not only the sweet singing of praises to Hashem. The physical act of voicing prayer helps a person to arouse his intentions. That then is Tefilah; the combination of the external service with the internal intention, which together, make a person a receptacle for receiving the goodness of the Creator. This service then becomes an offering before Hashem; the intention combined with the sweetness of the melody and the song of prayers.
The internal intentions of the heart and the external movement of the lips work together in another way to activate our prayer. Sometimes the words don't come out. Then the inner intentions can be used to stimulate the mouth to pronounce the prayers. On the other hand, there are times that the heart feels empty. The verbal expression of the prayer can arouse the heart to come alive. (This also explains why sometimes people shuckle when they pray. The physical motion pulls out the intentions of the heart, giving them expression as if they were words.)
The Yismach Moshe also explains that this idea represents a solution to an ancient controversy between the Rambam and one of the later sages, the Tola'as Ya'acov. The Rambam maintains that the primary duty of the Jew is to remember Hashem unceasingly and to believe in Him. On the other hand, the Tola'as Ya'acov disagrees with the Rambam, maintaining that the Jew must actively engage in Mitzvos in order to uphold the world. The intentions and the meditations of the heart (remembering Hashem, faith) work mutually with the active verbal expressions of the mouth. (dynamic performance of Mitzvos)
Tefillah truly is the Service of the Heart since it combines the mouth and the heart in unity of service to the Creator.