Kabbalah conceives of good and evil as opposite poles on the continuum of morality. This means that any situation or entity in life contains elements of both good and evil. Man's ability to safely descend down the moral continuum towards the pole of evil in order to transform it to good is a function of how strongly he is anchored in the upper regions of the continuum, near the pole of good. When he is firmly anchored in good, that is, he feels close in his relationship with G-d, he is not afraid to uncover any evil within himself or the world, and its discovery does not pose a threat to his overall belief in the eventual triumph of goodness and holiness.
Man's animal nature pulls him relentlessly toward the pole of evil away from consciousness of G-d, while his Divine soul pulls him toward the pole of good. The spirit of man ascends upward, but the spirit of the animal descends below, to earth. His ability to stay anchored in goodness thus depends on his success in giving his Divine soul precedence over his animal soul.
In the Talmud we are told of four sages, Rabbi Akiva and three of his pupils who engaged in mystical meditative techniques and ascended to transcendent realms of Divine consciousness. Ben Azzai gazed [upon the Divine glory] and died; of him Scripture [prophetically] states: Dear in the estimation of G-d is the death of His pious ones. Psalms 116:15. Ben Zoma gazed and lost his mind; of him Scripture states: You have found honey; eat [no more than] your fill, lest you become full and vomit it out. Proverbs 25:16. The other one [Elisha ben Avuyah, gazed and] became a heretic. Rabbi Akiva entered in peace and left in peace.
It is explained in Kabbalah that each of these sages attempted to rectify the sin of Adam and its effect on the world. Before the sin, good and evil existed in two separate realms and they were not intermixed in any way. When Adam and Eve ate the fruit of the tree of knowledge of good and evil, good and evil became intermixed, and the moral continuum referred to above was created. The mistake of Elisha ben Avuyah was that he tried to rectify the sin by dealing directly with evil and neglected to anchor himself first in good. Focusing entirely on the evil in the world, he lost the ability to reconcile its existence with a benevolent, caring G-d. The questions posed by evil were too great for him; he concluded that there is no G-d and became a heretic.
It is told that he observed someone who asked his son to climb a tree and bring him some nestlings. The son, who obliged, was fulfilling two commandments of the Torah at once: honoring his parent Exodus 20:12 and sending away a mother bird from its nest before taking its young. Deuteronomy 5:16. The reward promised for both of these commandments is long life, but the son accidentally fell from the tree and died. The anomaly was too much for Elisha ben Avuyah to bear.
Rabbi Akiva, in contrast, sought to rectify the sin of Adam by emphasizing the good and overcoming evil indirectly. Although he did not ultimately succeed, he nonetheless was able to emerge unscathed from the attempt. Since he remained fixed to the consciousness of G-d s goodness, the evil in the world did not constitute a contradiction for him.
He maintained this perspective until the end of his life. When caught teaching the Torah during the Hadrianic persecutions, he was sentenced to death. While the Romans were raking his flesh with iron combs, he recited the Shema , Hear, O Israel, G-d is our G-d, G-d is one, the declaration of the unity of G-d. He prolonged his recitation of the word one until he expired while saying it. The existence of evil did not pose any questions to his faith; rather, his faith was so strong that he was able to feel close to G-d even while his flesh was being raked with iron combs.