To the left is the commandment:
And now, O Israel, what does God your Godask of you, but to fear….
This is the commandment to fear God (yir'ah), or to constantly stand in awe of Him. Fear of God is the emotion that motivates the fulfillment of all the 365 negative commandments of the Torah.
The Fear that Augments Love
Here, the fear of God does not refer to the fear of punishment. Although useful to fall back on as a means of keeping ourselves from sinning (in times of spiritual immaturity, when unable to arouse any deeper motivation), fear of punishment is not really considered serving God Himself. For if we perform commandments to avoid punishment, we are not doing them for God's sake, but rather in our own interest.
True fear of God is founded on the fear of severing our bond of love with Him, our covenant of betrothal to Him. Thus, fear of God flows naturally out of the previous commandment, to love Him. If a person truly loves God, he will fear doing anything that might separate him from Him. This fear keeps the individual's consciousness focused on God and prevents him from doing anything prohibited by the Torah.
At first, this fear is not even conscious; it is just a natural component of one's love for God. Eventually, however, after having well-integrated the love of God into his daily life, one may begin to sense the initial infatuation wearing off; his fear then becomes that of losing his emotional involvement with God simply due to his own stagnation. Cognizant that love of God is a product of our awareness of His unity, this fear inspires us to transcend our present plateau of consciousness and seek newer insights in our conceptualization of Divinity.
Fear thus allows a person to transcend the limitations of his finite consciousness. As with regard to the effect of the elevated evil inclination on one's love of God, described above, so does one's fear of God join in the process of transmuting "love as water" (natural, pleasurable love) into "love as fire" (impassioned, unconsummated ardor), ever increasing the passion of love. As he ascends from level to level, each level of newfound love in time becomes "second-nature" to him, and again the fear of lapsing into the rut of complacency spurs him on to seek higher levels of insight with which to fan the flame of love. Thus, fear works together with love, the two joining to become the "wings" of the soul that constantly elevate all of one's good deeds, prayers, and learning.
On the second day of creation–the day corresponding to the sefirah of gevurah, the consciousness of the left–God severed the lower waters from the higher waters by means of the firmament. Our sages teach that "the lower waters cry: 'we also want to be close to God [as are the higher waters].'" For the first time, created reality experiences existential distance from God, the Creator. In both fear of separation and augmented longing, in love, to be close to God, creation cries out, with all its might (gevurah), to its Creator.
The Fear that Regulates LoveJust as fear serves to augment the intensity and passion of the flame of love, so does fear serve to regulate one's love for God. Implied in the fear of God is the apprehension of approaching Him too closely, lest the soul be annihilated in the Divine ecstasy of its passionate love for Him. This would negate God's will, for He created each being with a unique purpose in life, which cannot be fulfilled by any other being. Submission to God's will thus means restraining the passion of one's ecstasy to the extent necessary in order to remain alive and continue to fulfill his life's mission. Here, fear creates spiritual equilibrium, left (fear) balancing right (love). This level of fear, more "in tune" with God's ultimate will for creation than the previously described level of fear, is higher than the first in the root of the soul. The first level of fear is man's fear of being separated from God. The second level of fear reflects God's own fear that the soul misinterpret its purpose.