Why do we keep mitzvot? What should be our motivation for observing the Torah’s precepts?
In an article in Orot HaKodesh entitled “Three Levels of Holy Service,” Rav Kook analyzed different motivations in serving God. He discerned three levels, which he categorized as (1) the service of the Levites, (2) that of the kohanim (priests), and (3) the highest level — that of Moses, God’s servant.
The most common incentive to serve God is analogous to the service of the Levites. The Levites received tithes “in exchange for their work” (Num. 18:21). At this level, the motivation is personal gain. Mitzvot are valued for their material, psychological, and spiritual benefits. As this service of God becomes more refined, it no longer focuses on the reward. Yet, it remains based on simple, straightforward discipline.
The Levite service is a proper conduit to spread the Torah’s teachings in the areas of ethics and Jewish law. Nonetheless, it is an external form of serving God. The very word Levite means associate (see Num. 18:4). The Levites did not participate in the inner Temple service. They served as guards at the gates — on the outside. They lifted their voices in song, but the song of the Levites was a musical accompaniment to the actual Temple service.
Superior to the Levite service is that of the kohanim. The kohanim performed an inner service of God. They worked inside the Temple. This is the mystical service of holy tzaddikim, who are the foundations of the world. These saintly souls concern themselves with the secrets of the universe. They seek to ‘nourish’ the supernal spiritual worlds by giving strength and greatness to God’s Divine Presence. Because of the altruistic nature of the priestly service, the Torah describes it as a ‘gift’ — “This is the gift of service that I have given you as your priesthood” (Num. 18:7).
The highest level is the service of Moses. The Zohar refers to Moses as “ra’aya meheimna,” "the faithful shepherd,” for his concern was solely for the people under his charge. This sublime level of selflessness transcends all spiritual realms. It goes beyond the efforts of the righteous to nourish and increase them. In accordance with the flawless purity of his intentions, Moses’ prophetic visions were seen through a ‘clear lens,’ an “aspaklaria me'ira.” Compared to his brilliant prophetic gift, all other divine blessings are like the weak light of a candle in the blazing midday sun.
At the end of his life, Moses merited the title “God’s servant": “It was there in the land of Moab that God’s servant Moses died, at God’s word” (Deut. 34:5).
A servant of God is always ready to serve and influence, without any thought of benefit or gain. He is not even motivated by the reward of noble, spiritual blessings. By virtue of his pure and selfless service, Moses merited to be called ‘God’s servant.’ “Moses rejoiced in the gift of his portion, for You called him a ‘faithful servant'” (from the Sabbath morning prayers).
(adapted from Orot HaKodesh vol. III, pp. 201-2)