The portion of Mishpatim contains the law of the goring ox. There are two categories: the "shor tam," a bull not known to be a gorer, and the "shor mu'ad," a bull that has gored three times. Such an animal is dangerous and likely to gore again.
The Torah can be understood on many levels. This law applies not only to animals but also to a person's soul. The ox symbolizes the animal soul (every Jew has two souls: a Divine soul and an animal soul.) The animal soul is not necessarily bad. It has many positive qualities and and can be harnessed for good. Nonetheless, like the physical ox, it must be watched to prevent it from inflicting damage.
The natural state of the animal soul is "a bull not known to gore." As it is created, the animal soul does not crave forbidden things, only those that are permissible and necessary to sustain life. If the animal soul falters and commits a sin, it is the exception rather than the rule, and runs contrary to its true nature. In this instance it is relatively easy to repent and repair the damage.
However, if a person commits the same sin over and over again "until it seems permissible," he is considered "a bull that has gored three times." Having already been reinforced several times, his negative behavior is now second nature to him, and he is considered likely to repeat it in the future.
How to turn "a known gorer" back into "a bull that is not known to gore"? Simply by training it. According to Maimonides, the transformation is complete "when little children can poke [the ox] and it still doesn't gore."
The same rule applies in our service of G-d. The "repeat offender" must work hard on refining his animal soul and weakening its desires. Then, when he finds himself facing the exact same temptation, yet he remains strong and doesn't falter, his status reverts to "a bull that is not known to gore."
This is not easy to accomplish, so the Torah offers us another method of attack. According to Maimonides, when a "known gorer" acquires a new owner, the slate is cleaned and the animal is considered "a bull that is not known to gore." Because the new owner relates to it differently, the animal's nature also changes for the good.
In spiritual terms, any Jew who wants to undergo a similar transformation must also acquire a new "owner," immersing himself completely in the realm of holiness: learning Torah, doing good deeds and engaging in prayer. His ingrained bad habits will automatically lose their grip on him, and he will become "tam" - literally "perfect and whole."
Adapted from Likutei Sichot, vol. 36