In the beginning of the second chapter of his Hilchot Teshuba, the Rambam (Rabbi Moshe Maimonides, 1135-1204) describes the level of "Teshuba Gemura" – "complete repentance." A sinner achieves the highest level of repentance, the Rambam writes, when he is confronted with the same situation in which he had sinned originally, but this time succeeds in withstanding the test out of a desire to repent. If the individual refrains from the sin not out of fear or lack of ability, but strictly because he has repented, then he has reached the level of "Teshuba Gemura." The Rambam gives the example of a person who committed a sin with a woman, and later finds himself alone with the woman and in the same physical condition as he was the first time. If he abstains from sin because of repentance – and not because he is afraid of being discovered or because he is physically frail – then he has achieved the highest level of repentance.
Nevertheless, the Rambam adds, even if a person does not repent until he grows old and frail, such that he in any event can no longer commit the sinful act, his repentance is nevertheless accepted and valuable. A sinner is considered a "Ba’al Teshuba" ("penitent") even if he does not repent until he lies on his deathbed. Although he has not achieved the highest level of repentance, he has nevertheless repented and his repentance is accepted.
The Rambam in this context also delineates the basic components of Teshuba. He writes that repentance requires making a firm resolve in one’s mind to abandon his path of sin, and eliminating the sin entirely from one’s thoughts. He must also regret having committed the act, to the point where God Himself, who knows all future events, can testify that he will never repeat the sin. The Rambam emphasizes that Teshuba requires both verbal confession as well as mental resolve to never repeat the sin again. If a person confesses without committing himself to refrain from the sin in the future, he is comparable to a person who immerses in a Mikveh while holding in his hand an object of ritual impurity ("Tobel Ve’sheretz Be’yado"). Obviously, the immersion cannot be effective in eliminating his ritual impurity so long as he holds an object of impurity. Similarly, verbal confession and prayer are meaningless if a sinner does not resolve in his heart to repent and change his ways.
Finally, the Rambam mentions that Teshuba requires specifying the sin, rather than simply confessing generically. He draws proof from the fact that when Moshe pleaded with God to forgive Beneh Yisrael for the sin of the golden calf, he explicitly stated that the nation sinned by fashioning a golden idol (Shemot 32:31). This demonstrates that confession requires stating the particular sin which one committed, rather than simply stating, "I have sinned."
Summary: Teshuba (repentance) requires verbal confession – in which one specifies the particular sin he committed – as well as firm, mental resolve to change one’s conduct and not to repeat the sin. The highest level of repentance is achieved when a person finds himself in the same situation in which he committed the sin, but refrains as a result of his decision to change.
