The commentaries dispute the meaning of this enigmatic pasuk. Rashi explains that the nation was to accept communal responsibility for observance of the Torah. This weighty obligation is not easily fulfilled. Some sins are performed in the open. These can be addressed by the community. However, many of the obligations of the Torah are performed in the privacy of one’s home or in the heart. How can the community bare responsibility for these private areas of observance? Rashi understands the pasuk to respond to this issue. The community is obligated to encourage Torah practice in all of its observable forms. This obligation does not extend to those observances that are hidden from the community. In these areas the community is not duty-bound to ensure observance. This is the Almighty’s domain. He will deal with the private practices and thoughts of the human being.
Nachmanides offers an alternative interpretation of the pasuk. Not all of our sins are revealed to us. Sometimes we commit a sin unknowingly. The pasuk explains that we are not responsible for these errors. However, we must apply our full attention to repenting from those iniquities of which we are aware.
Nachmanides comments can perhaps be understood on a deeper level. Repentance assumes that we have the ability to control our actions. This is not always the case. Sometimes we are confronted with a behavior we are truly incapable of controlling or altering. In general, these behaviors stem from motivations we do not fully understand. Because these motivations are hidden they are impossible to uproot. We find ourselves powerless to correct our behavior. Possibly, Nachmanides is discussing this issue. These sins are referred to as hidden. This is because the observable sinful behavior is only the outward expression of the hidden aspects of our personality. We are not held responsible for these sins that we cannot control.
“And you will then return to Hashem your G-d and you will listen to His voice as I have commanded you today – you and your children – with all your heart and with all your soul.” (Devarim 30:2)
Moshe tells Bnai Yisrael that they may sin and be exiled from the land of Israel. They will be subjected to the terrible punishments previously described in the Torah. However, Moshe assures the nation that eventually the people will return to Hashem. Our pasuk describes perfect or complete teshuva – repentance. Total repentance involves the heart and the soul. The Torah often describes complete commitment with this phrase. We are to serve the Almighty with all our hearts and souls. Complete love of Hashem is also described with this phrase. What do "heart" and "soul" mean in this context?
Sforno explains each of these phrases. He explains that a complete heart means that the person has no doubts. A complete soul indicates that all desire to repeat the sin has been uprooted. 
We commonly understand the teshuva as abandonment of a sinful behavior. Based on this understanding, we would define complete repentance as total abandonment of the evil behavior. Yet, Sforno seems to require more than mere cessation of the behavior. He asserts that we must also commit our heart and soul. Why is this additional aspect necessary? In order to fully understand Sforno's comments, we must carefully consider the nature of repentance.
Let us begin by considering a related problem. Teshuva must be accompanied by a verbal declaration. This declaration is a confession and a commitment not to return to the sinful behavior. Repentance and confession can take place at any time during the year. Yet, there is a special obligation to repent and confess on Yom Kippur. Let us assume a person sinned. The person regretted the sin. The individual repented and confessed the sin. Now, Yom Kippur arrives. Must the person repeat the confession? Halacha requires that the person repeat the confession. This requirement applies even if the sin has not been repeated. In fact, even if the person never repeats the wrongdoing, the individual is required to repeat the confession each Yom Kippur. Why does halacha demand these repeated confessions?
If we assume that teshuva is a cessation of sinful behavior, it makes little sense to require repeated confessions over a sin that has long been abandoned. However, this is the requirement! This tells us that there must be another aspect to repentance. Beyond the abandonment of the external behavior, an internal reorientation is needed. We must change our attitudes towards our previous behavior. Before, we desired the sinful activity. We were enticed by it. With repentance we come to see the behavior as deplorable and destructive. We no longer harbor the desire to engage in the sinful activity. Teshuva does not end with cessation of a physical activity. The process must continue until one's perceptions of the sin are changed. This requires ongoing review. Through reviewing our behavior annually, we can slowly change our internal attitudes. We can reorient our outlook on the sinful activity. This is the purpose of repeating the confession.
We can now better understand the Sforno's comments. Teshuva mends one's behavior and soul. Repentance involves an external change and an internal reorientation. Sforno is explaining the elements of this reorientation. He is defining the internal elements of teshuva.
The first element is changing one's perception of the sin. The second is the complete uprooting of the desire to commit the sin. Let us consider each of these elements.
Not every repentant individual is completely successful in changing his or her perceptions of the previous behaviors. This is because there are various motivations for repentance. It is naïve to assume that repentance is uniformly accompanied by a complete conviction in the evil of the previous behavior. For example, teshuva may be motivated by a general sense of unhappiness. In such individuals repentance represents an attempt to begin life anew. This person seeks meaning and self-fulfillment to replace an empty lifestyle. This person cannot identify the specific fallacies of the previous life-style. Neither can the person articulate the benefits of his or her new life-style. This understanding is replaced by a general sense of wellbeing and religious fulfillment. Certainly, this person has repented. However, this repentance lacks a thorough reevaluation. The person's actions have been corrected. The perceptions are still imperfect.
It is also true that repentance is not always accompanied by an uprooting of the desire to commit the sin. One's commitment to a new life-style can also vary. Every individual feels conflicting desires. We choose to pursue some desires and attempt to ignore or suppress others. Few individuals can claim a complete commitment to Torah – devoid of all conflict. Most of us learn to live with some level of personal conflict. A person may observe Shabbat, kashrut and the other mitzvot. Yet, this person recognizes that sometimes the urge exists to ignore a specific commandment or law. This individual is acting properly. However, this person’s inner feelings are not in congruity with the individual’s behavior.
We can now appreciate Sforno's description of complete teshuva. In complete repentance there exist perfect congruity between action, understanding and feeling. Clear understanding has vanquished conflicting desire. As a result, the internal and external are consistent. In the Sforno's words, the heart and soul are committed to the behavior exhibited by the body.
“And now write for yourselves this song. And teach it to Bnai Yisrael and place it in their mouths. This is order that this song will serve as a witness to Bnai Yisrael.” (Devarim 31:19)
Hashem tells Moshe that the time of his death is approaching. Moshe is to create a written record of the shira – the song that Hashem has taught him. He must also teach the song to the people. What is this song that Moshe must transmit? The Talmud indicates, in Tractate Sanhedrin, that the shira is the Torah. Moshe is to record the Torah and teach it to Bnai Yisrael.
The Talmud further explains that it is a mitzvah for every man of Bnai Yisrael to write a Sefer Torah.
Maimonides discusses this commandment in his Mishne Torah. He explains that this requirement is one of the six hundred thirteen mitzvot. He adds that it can be fulfilled through writing or correcting a single letter in a complete Sefer Torah.
Rabbaynu Asher explains that we no longer fulfill this commandment through the writing of a Sefer Torah. Instead, we observe the command through writing copies of the Talmud, its commentaries and other works of the Torah. Why has the mitzvah changed? Rabbaynu Asher explains that the mitzvah is to create the works needed for one’s personal pursuit of Torah knowledge. In earlier times the Torah was studied directly from the Sefer Torah. In that period it was appropriate to create a personal copy of the Sefer Torah. Today, the Sefer Torah is kept in the synagogue. It is read before the congregation. It is not used for personal study. We employ other works for learning Torah. Our obligation is to acquire these essential works. Rav Moshe Feinstein Ztl adds that the mitzvah does not require the actual writing of these various works. Today, we can fulfill the commandment through the purchase of these sefarim – books.
Bait Yosef rejects this interpretation of the mitzvah. He argues that we are still required to write an actual Sefer Torah. We cannot fulfill this mitzvah through writing or purchasing other sefarim. This is also the opinion of Maimonides and other authorities.
Rabbaynu Asher’s position is difficult to understand. He agrees that the original mitzvah was to write a Sefer Torah. He maintains that the mitzvah is now transformed and can be fulfilled through the purchase of sefarim. How can these sefarim substitute for the Sefer Torah?
In order to answer this question some background is required. The Torah is composed of two components. These are the Written Law and the Oral Law. The Written Law is the Chumash. The Oral Law is the Talmud and the explanation of the Torah. Both the Written and the Oral Law were given to Bnai Yisrael at Sinai.
Why is the Chumash referred to as the Written Law and the Talmud and commentaries defined as the Oral Law? This is because the Chumash is to be recorded in the form of the Sefer Torah. It is to be studied in this written form. The Talmud and the commentaries are not to be formally recorded. They are intended to be studied as an orally transmitted tradition.
The Talmud explains in Tractate Gittin that it is not permitted to study the Written Law without direct reference to a text. It is also prohibited to transcribe the Oral Law and transform it into a written form.
Today the Oral Law is committed to writing. Why is this permitted? The Talmud explains that this alteration in the very nature of the Oral Law is required in order to assure its preservation.
We can now better understand Rabbaynu Asher’s position. Rabbaynu Asher maintains that the mitzvah has always been to acquire sefarim for study. In other words, the mitzvah is an extension of the obligation to study the Torah. Originally, the Sefer Torah was the only written book of the Torah. The Oral Law could not be transcribed. This meant that the only book required to study the Torah was the Sefer Torah. All other Torah knowledge was to be communicated orally. In order to fulfill the mitzvah one was required to copy the Sefer Torah.
The decision to allow the Oral Torah to be written created an abundant source of other sefarim. The Sefer Torah was no longer the exclusive or primary written work used in Torah study. These other sefarim of the Oral Law became the means through which the Torah was studied. Now, the acquisition of these sefarim fulfilled the mitzvah of securing the means for Torah study.
 Rabbaynu Shlomo ben Yitzchak (Rashi), Commentary on Sefer Devarim 29:28.
 Rabbaynu Moshe ben Nachman (Ramban / Nachmanides), Commentary on Sefer Devarim 29:28.
 Rav Yisroel Chait, Editor’s notes.
 Sefer Devarim 11:14.
 Sefer Devarim 6:5.
 Rabbaynu Ovadia Sforno, Commentary on Sefer Devarim 30:2.
 Rabbaynu Moshe ben Maimon (Rambam / Maimonides) Mishne Torah, Hilchot Teshuva 2:8.
 Mesechet Sanhedrin 21b.
 Mesechet Sanhedrin 21b.
 Rabbaynu Moshe ben Maimon (Rambam / Maimonides) Mishne Torah, Hilchot Sefer Torah 7:1.
 Piske HaRa’ash al Hilchot Sefer Torah 2b.
 Rav Moshe Feinstein, Igrot Moshe, Orech Chayim, volume 4, p 56.
 Rav Yosef Karo, Bait Yosef Commentary on Tur, Orach Chayim 270.
 Mesechet Gittin 60b.
 Mesechet Gittin 60a.