Note: Many other mitzvot besides the 12 counted, are found in Va'etchanan, but they are counted elsewhere in the Torah. This is not uncommon, but what it means is that the mitzva-count of a sedra is often not an accurate indicator of the actual mitzva content of the sedra. This is so of several sedras, very much so with this Va'etchanan.
Kohen - First Aliya - 11 p'sukim - 3:23-4:4
[SDT] The proper method of Jewish prayer is to first say words of praise about G-d, then make requests of Him. This is the structure of the Amida. We learn this from Moshe Rabeinu who first says that G-d has begun to reveal His greatness to Moshe... and then Moshe asked to be allowed to enter the Land.
[SDT] The Baal Shem Tov commented that Moshe, who had learned the entire Torah, Written Word and Oral Law, from G-d Himself, used the term "You have begun to show me Your greatness..." The more one learns Torah, the more one learns about G-d, the more one will realize that he has just begun to understand Who G-d is.
G-d refused this request and forbade Moshe to ask again. Moshe ascended a mountain from where he saw the Land. G-d then told him to transfer the authority of leadership to Yehoshua.
According to the Vilna Gaon's analysis of the Book of D'varim, this ends the first section of Moshe's message to the People.
He next proceeds to review the laws and statutes (Torah and mitzvot) by which the people are now to live... in Eretz Yisrael.
Neither should the Torah be added to nor detracted from [these are counted elsewhere as mitzvot]. Another warning against idolatry follows.
Then, "And you who cling to G-d are all alive today". (The Gemara teaches that this is one of the many references to T'CHIYAT HAMEITIM in the Torah.)
Nor may one add or subtract to the total of the mitzvot. To treat a Rabbinic mitzva as a Torah law, or vice versa, would be an example of the other aspect of these mitzvot. The spirit of these prohibitions (if not the actual definitions) would include treating (and/or teaching) a CHUMRA as if it were required, or vice versa (claiming that something that is prohibited is "only" a chumra.
Here we go again...
Prolonged exile has taught us that the Torah can be kept, must be kept, no matter where a Jew finds himself. This was one of the reasons that the Torah was given at Sinai, prior to entry into the Land. On the other hand, one should not lose sight of the fact, repeated often by Moshe Rabeinu in D'varim, that G-d has always intended us to observe His mitzvot IN THE LAND OF ISRAEL. Are there more mitzvot to keep in Israel than outside? YES. But maybe more significantly, every mitzva - even those that are performed all over the world, can reach their full potential ONLY in Israel.
This is a message that each of us has to realize, understand, and internalize. Then we must spread this message to family and friends abroad who feel that they "have everything we need to be fully Jewish" in their respective religious communities around the world. AND the vital significance of Torah AND Israel to our lives as Jews must be taught to those less committed Jews here in Israel and abroad.
On the other hand, we must not forget that Israel today is not the realization of the Dream, but rather a step on the road to the Complete Redemption, the restoration of Zion and Jerusalem, the rebuilding of the Beit HaMikdash, and the coming of Mashiach. This idea helps us refocus after the mourning period that ended with the 10th of Av, and is an appropriate theme to usher in the period of consolation and repentance.
We must be careful to preserve and perform the mitzvot because (among other reasons) it is the mitzvot that project Judaism as an intelligent religion to the nations of the world. This in turn, sanctifies G-d's Name. We must be infinitely careful to remember and transmit to our children, the "Sinai Experience". Moshe describes for the new generation the details of Matan Torah. He includes a specific warning against the potentially idolatrous thoughts caused by the combination of the magnificent, tangible universe in which we live and the Invisible G-d.
G-d had taken us out of Egypt in order to make us His Nation. He got angry at me, says Moshe, and forbade me to enter the Land. Again, Moshe warns the People against abandoning the covenant with G-d after his (Moshe's) passing.
The next portion is read on Tish'a b'Av morning... In spite of the many warnings against idolatry, Moshe prophesies (predicts) that there will come a time when the People will turn from G-d and be exiled from their Land. It will then come to pass that the People will seek out G-d and return to Him.
Moshe emphasizes the uniqueness of the People of Israel and their special relationship with G-d and beseeches the People to remain faithful to Torah and mitzvot. One can hear a pleading in his voice, as if he is begging the people not to go in the direction of his prophecy.
These (the mitzvot about to be presented) were taught by Moshe to the People following the Exodus in the lands on the East Bank of the Jordan.
V'zot HaTorah... said when the Torah is lifted, comes from D'varim 4:44. In the Siddur, the words AL PI HASHEM B'YAD MOSHE are added. That phrase appears 4 times in Bamidbar, but 9:23 seems it.
[SDT] There are interesting differences between this version of the Decalogue and the one in Yitro - the most notable being the famous "Shamor v'Zachor" of Shabbat. Generally, "Zachor" is interpreted as referring to the positive mitzvot and aspects of Shabbat, whereas "Shamor" is taken as warning against violation of prohibitions. The traditional minimum of two Shabbat candles (although one candle would satisfy the halacha), are said to represent these two dimensions of Shabbat.
It is the intertwined nature of the positive aspects of Shabbat and its prohibitions that is "responsible" for Kiddush on Friday night being obligatory upon women. Rather than treat Kiddush as a pure "time-related positive mitzva" which would probably mean that women would be exempt, we view Kiddush as part of the whole of Shabbat, which of course, means full and equal obligation for men and women. The two sides of Shabbat were commanded B'DIBUR ECHAD and are inseparable.
Following the same idea through to Havdala, we have a dispute among authorities as to whether women are obligated. Majority opinion views Havdala as the Shabbat-ending counterpart of Kiddush, and claims that women are obligated on Havdala. A minority opinion sees Havdala as detached from Shabbat, which gives it more of a time-related positive nature, and claims that women are exempt. The conclusion in halacha is that women must treat Havdala as an obligation, but should hear it being said by a man, if possible. If not, a woman must "do" Havdala on her own. (Additional questions exist concerning both b'samim and the candle – additional reasons to prefer hearing Havdala from a man.)
The mitzva here deals exclusively with thoughts and feelings; its counterpart in Yitro involves acting on those feelings. V'LO TIT'AVEH in a way, completes a set of prohibitions, that starts with obviously sinful acts - murder, stealing, etc. to a feeling in the heart (LO TACHMOD) which can, and often does, lead to acts which are "milder", but nonetheless "problematic". For example, if a person is jealous of a friend's sweater, and comments about it often enough, the friend might just feel uncomfortable enough to give it to the jealous friend. Nothing wrong, per se, in complimenting someone's sweater, but in this case it is part of the prohibition of LO TACHMOD. And V'LO TIT'AVEH is the feelings even without anything else.
This is a very crucial episode in understanding our Chain of Tradition and the method of transmission of the Oral Law. It made not only Moshe Rabeinu vital to our understanding G-d's Word, but so too the Moshe Rabeinus of every generation. This is so for prophets, during the period in Jewish History when we had prophecy, but it also extends to this day in the way Tradition is passed from one generation to the next. We can say that we have a serious obligation to accept Torah from our parents and teachers, precisely because those that stood at Sinai did not want to hear G-d's voice directly beyond the first tweo commandments.
Moshe emphasizes that G-d agreed to the People's request.
And yet again, Moshe links observance of mitzvot with the only proper environment for Jewish life - Eretz Yisrael. (This idea is actually expressed in THREE different ways in the final p'sukim of this Aliya.)
"Love" G-d with your entire being . (Many mitzvot and Jewish practices and attitudes are considered manifestations of Love of G-d.) We must study and teach Torah  (for practical purposes AND purely for the sake of learning). We are to recite the Shma twice daily , wear T'filin on the arm  and above the center of the forehead , and put a mezuza on our doorposts .
[SDT] The mitzva of Learning and Teaching Torah can be fulfilled with one's head, one's intellect. Tell someone a Dvar Torah and you both have fulfilled V'SHINANTAM L'VANECHA. But, tell that same Dvar Torah in an animated way that shows love of G-d and that ignites the emotion of the listener, so that he not only adds to his knowledge of Torah, but his excitement and enthusiasm for Torah and Mitzvot has increased, then you have fulfilled an additional mitzva, V'AHAVTA ET HASHEM ELOKECHA, to love G-d with all your heart. (Sefer HaChareidim)
Ashkenazim (most) say two brachot on T'filin, one on each. S'faradim usually do not. But do these practices indicate whether T'filin is (are) a mitzva (two mitzvot)? Not necessarily.
Regardless of how secure one is in one's belief, intermarriage and other close contact with alien cultures will have an adverse effect upon the individual Jew and on the Jewish People.
We must destroy the idolatry in the Land. We must always keep in mind the basis upon which G-d has built His relationship with us.
It is because of G-d's love for us and His promises to our ancestors that He has taken us out of Egypt.
Know that G-d is trustworthy to keep His promises and reward those who properly follow His ways, as well as punish those who do not.