כי המצוה הזאת אשר אנכי מצוך היום, "For this commandment which I command to you today, etc." Why did the Torah have to write the word "today?" Besides once the Torah had told us that the Torah is not hidden from you, is it not clear that it is not very distant? Why did the Torah bother to write לא רחוקה היא? Why did the Torah have to remind us that Torah is not beyond the ocean? Even if it were, it is an accessible location and we could have secured it by means of ships! Perhaps the Torah refers to two factors which contribute to failure of Torah observance by the people: 1) Ignorance of what is written in the Torah. 2) The difficulty in keeping the commandments. Moses told the people that although prior to his going up on Mount Sinai the Torah had indeed been in the heavens it was no longer in heaven but accessible to all. He told the people that it was not in a distant land or across the sea, i.e. that although he personally had not been favored by G'd to keep these commandments on holy soil, they would be more fortunate. When Moses asked the rhetorical question: "it is not across the ocean so that you would have to ask who would cross the ocean to get the Torah for you," he lamented his own inability to even cross the Jordan to be able to keep the Torah commandments applicable on the other bank. He portrayed the Jordan as an insurmountable obstacle for him, much like crossing an ocean. Nonetheless, the principal meaning of this line is that there are no valid excuses for not observing Torah. It is easily accessible
ולא רחוקה היא, so that you have to ask the leading Torah scholars of your generation who live a long way from you to explain how to observe this commandment. You can easily observe this commandment even in the Diaspora where you may not have any Torah scholars nearby.
מי יעלה לנו השמימה, “who will ascend to heaven on our behalf?” the respective first letters in these four words, when read separately and consecutively spell מילה, circumcision. It is a hint that it was the merit of the performance of the commandment of circumcision that enabled Moses to ascend Mount Sinai and receive
לא בשמים היא, “it is not in heaven;” it is possible that the reason Moses makes this point is because prior to bringing the Torah to the people it had indeed resided in heaven, and we have quoted arguments offered by the angels opposing its descent to earth.
R. Abdimi b. Dosa spoke thus: "What is meant by the passage (Deu. 30:12.): It is not in heaven, neither is it beyond the sea. It is not in heaven means that even if it were in heaven, one would have to ascend to reach it; neither is it beyond the sea, i.e., even if it were beyond the sea, one would have to cross the sea to reach it."
Raba said: "It is not in heaven, means that knowledge cannot be found in he who exalts himself [in wisdom] as high as the heavens; Neither is it beyond the sea, means that neither is it with him who considers his opinion as broad as the sea."
R. Jachanan said: "It is not in heaven, means that it cannot be found among presumptuous men; Neither is it beyond the sea, means that it cannot be found among travelling merchants and tradesmen."
בפיך ובלבבך לעשותו, “with your mouth and your heart to perform it.” The Torah mentions three things here; the mouth, the heart, and the performance. All the laws of the Torah are included therefore as belonging to one of these three categories. There are commandments which require to be fulfilled by use of the mouth; others can be fulfilled by means of the heart only; still others require “performance,” i.e. the involvement of other organs and parts of our bodies...
Nachmanides, at the end of verse 11 writes as follows: the words בפיך ובלבבך refer to the subject of penitence, repentance, a commandment spelled out in verse 2 of our chapter. When the Torah speaks of this repentance it draws attention to the fact that it is not so difficult to fulfill this commandment. The Torah does not demand all sorts of difficult tasks such as ascending to heaven or crossing the ocean for a person to have fulfilled this commandment. All it takes to become a true penitent is the mouth and the heart. It may be performed anywhere; you do not even have to come to Jerusalem and the Temple to have your repentance accepted by the Lord. It is the easiest thing to do, i.e. כי קרוב אליך הדבר מאד לעשותו, “the matter is right at hand for you to carry out.” All you need is to employ your mouth and your heart.
וזה הוא תנור של עכנאי מאי עכנאי אמר רב יהודה אמר שמואל שהקיפו דברים כעכנא זו וטמאוהו תנא באותו היום השיב רבי אליעזר כל תשובות שבעולם ולא קיבלו הימנו אמר להם אם הלכה כמותי חרוב זה יוכיח נעקר חרוב ממקומו מאה אמה ואמרי לה ארבע מאות אמה אמרו לו אין מביאין ראיה מן החרוב חזר ואמר להם אם הלכה כמותי אמת המים יוכיחו חזרו אמת המים לאחוריהם אמרו לו אין מביאין ראיה מאמת המים חזר ואמר להם אם הלכה כמותי כותלי בית המדרש יוכיחו הטו כותלי בית המדרש ליפול גער בהם רבי יהושע אמר להם אם תלמידי חכמים מנצחים זה את זה בהלכה אתם מה טיבכם לא נפלו מפני כבודו של רבי יהושע ולא זקפו מפני כבודו של ר"א ועדיין מטין ועומדין חזר ואמר להם אם הלכה כמותי מן השמים יוכיחו יצאתה בת קול ואמרה מה לכם אצל ר"א שהלכה כמותו בכ"מ עמד רבי יהושע על רגליו ואמר (דברים ל, יב) לא בשמים היא מאי לא בשמים היא אמר רבי ירמיה שכבר נתנה תורה מהר סיני אין אנו משגיחין בבת קול שכבר כתבת בהר סיני בתורה (שמות כג, ב) אחרי רבים להטות אשכחיה רבי נתן לאליהו א"ל מאי עביד קוב"ה בההיא שעתא א"ל קא חייך ואמר נצחוני בני נצחוני בני
And this is known as the oven of akhnai. The Gemara asks: What is the relevance of akhnai, a snake, in this context? Rav Yehuda said that Shmuel said: It is characterized in that manner due to the fact that the Rabbis surrounded it with their statements like this snake, which often forms a coil when at rest, and deemed it impure. The Sages taught: On that day, when they discussed this matter, Rabbi Eliezer answered all possible answers in the world to support his opinion, but the Rabbis did not accept his explanations from him.
After failing to convince the Rabbis logically, Rabbi Eliezer said to them: If the halakha is in accordance with my opinion, this carob tree will prove it. The carob tree was uprooted from its place one hundred cubits, and some say four hundred cubits. The Rabbis said to him: One does not cite halakhic proof from the carob tree.
Rabbi Eliezer then said to them: If the halakha is in accordance with my opinion, the stream will prove it. The water in the stream turned backward and began flowing in the opposite direction. They said to him: One does not cite halakhic proof from a stream.
Rabbi Eliezer then said to them: If the halakha is in accordance with my opinion, the walls of the study hall will prove it. The walls of the study hall leaned inward and began to fall. Rabbi Yehoshua scolded the walls and said to them: If Torah scholars are contending with each other in matters of halakha, what is the nature of your involvement in this dispute? The Gemara relates: The walls did not fall because of the deference due Rabbi Yehoshua, but they did not straighten because of the deference due Rabbi Eliezer, and they still remain leaning.
Rabbi Eliezer then said to them: If the halakha is in accordance with my opinion, Heaven will prove it. A Divine Voice emerged from Heaven and said: Why are you differing with Rabbi Eliezer, as the halakha is in accordance with his opinion in every place that he expresses an opinion? Rabbi Yehoshua stood on his feet and said: It is written: “It is not in heaven” (Deuteronomy 30:12). The Gemara asks: What is the relevance of the phrase “It is not in heaven” in this context? Rabbi Yirmeya says: Since the Torah was already given at Mount Sinai, we do not regard a Divine Voice, as You already wrote at Mount Sinai, in the Torah: “After a majority to incline” (Exodus 23:2). Since the majority of Rabbis disagreed with Rabbi Eliezer’s opinion, the halakha is not ruled in accordance with his opinion.
The Gemara relates: Years after, Rabbi Natan encountered Elijah the prophet and said to him: What did the Holy One, Blessed be He, do at that time, when Rabbi Yehoshua issued his declaration? Elijah said to him: The Holy Blessed One, smiled and said: My children have bested Me; My children have bested Me.