We say in the kedusha of Shabbos Mussaf  ויחון עם המיחדים שמו ערב ובקר בכל יום תמיד פעמים באהבה שמע אומרים Hashem should give grace to the nation that recites the Shemah Yisrael twice daily with love. Similarly, at the end of Tachanun in the part of Shomer Yisrael, we ask Hashem to protect us from our enemies for the sole reason that we recite the Shemah ואל יאבד ישראל האומרים שמע ישראל also ואל יאבד גוי אחד המיחדים שמך ה’ אלקינו ה’ אחד. We see from here that the mere reciting of the daily Shemah Yisrael serves as a reason for Hashem to protect us and that we shall find favor in Hashem’s eyes.

This protective power of Shemah is hinted in our parsha in the passuk (20,2,3). Before Yisrael goes out to battle, the Kohen approaches the people and says “שמע ישראל”  whereupon Rashi comments in the name of Chazal (Sotah 42b) that even if you possess only the merit of the Shemah Yisrael you are still worthy of being saved. Even the Philistine giant Galiyas, who was beheaded by Dovid Hamelech, realized this special protection of the recital of Shemah. It was for this reason that he approached the camp of Am Yisrael specifically in the morning and night in order to place fear in their hearts which would disable them from reciting the Shemah (Sotah 42b).

This concept is also hinted in the passuk which concerns the returning of a lost object whereupon it says והתעלמת that in special situations one can “close his eyes” from seeing the lost object and thereby be freed from the obligation to return it (Berachos 19b). For instance an elderly person is not required to occupy himself in returning the object to its owner. Chazal state (Berachos 6) that Hashem also observes the mitzvos. Therefore we can say that in special situations Hashem also turns a blind eye from our aveiros. Our transgressions against Hashem place us in jeopardy of being “lost” like an אבידה as we beseech Hashem every day to save us from this fate ואל יאבד ישראל. However, by our saying the Shemah, it is as if Hashem turns away His face from viewing us as being in our state of an aveidah and instead saves us from the enemy who seeks to destroy us completely. That is why the gematriah of שמע ישראל is the same as והתעלמת for it is this zechus of Shemah that causes  Hashem to remove His focus from our state of being lost.

During this same address of the Kohen to the people who are about to go to war, he announces whoever is fearful from the aveiros that he possesses should not go to battle but rather return home (Devarim 20,8). The Ohr Chayim Hakadosh explains that not to be killed in warfare is a miracle and anyone who possesses transgressions is not worthy that a miracle should happen to him and his mazal will bring him to be fearful. This Chazal seems to contradict themselves for above on the words שמע ישראל, they said that the merit of reciting the Shemah Yisrael alone will protect you in battle? 
We can answer this contradiction with an explanation from the Eretz Tzvi on the Chazal (Berachos 15b)

תני רב עובדיה קמיה דרבא ולמדתם שיהא למודך תם שיתן ריוח בין הדבקים עני רבא בתריה כגון על לבבך על לבבכם בכל לבבך בכל לבבכם עשב בשדך ואבדתם מהרה הכנף פתיל אתכם מארץ אמר רבי חמא ברבי חנינא כל הקורא קריאת שמע ומדקדק באותיותיה מצננין לו גהינם

Whoever is meticulous in reciting the three parshiyos of Shemah will thereby merit to a cooling off of Gehenom. Carefulness in the reading of Shemah means not to read two words as one, for then they will not be pronounced properly. How does this exactness in reading the Shemah cool off one’s Gehenom which he is receiving for his various transgressions?
He explains that just as we find that accidental aveiros can transform into intentional ones under certain circumstances (Devarim 29,18 Rashi) so too there is a segulah to take big aveiros and make them into smaller ones. This special segulah is not something to purchase or to afflict oneself with fasting. It is simply to recite the Shemah each word individually, separating the pronunciation of the end of one to the beginning of the other. If you choose to daven from the right Siddur, its printers have conveniently drawn lines between these run on words and they serve as red lights to take notice and “brake to make the break”. For instance,בכל לבבך על לבבך ואבדתם מהרה ושמתם את וקשרתם אותם as mentioned in the Gemarah, that without the proper intentional separation one will definitely not escape from reading these words as mutants alien to Lashon Hakodesh. Some of these distortions that we create are outright frightening. ולמדתם אותם את בניכם = ולמדת מותם את בניכם  וראיתם אותו = וראיתם מותו,, וקשרתם אותם = וקשרת מותם, ועשיתם אותם = ועשית מותם. If not careful, we unknowingly are arousing tragedy chas veshalom.

What would have been one long run-on sentence of 248 words, by discipline and patience is broken up into smaller pieces of 248. This pulling of the reins and self-control not to rush is the segulah midah keneged midah. Hashem also takes your big aveiros and chops them into smaller ones. By conducting oneself in this manner, number one, the teshuvah process is facilitated since now there exist only smaller aveiros which do not necessitate a rigorous teshuvah. Secondly, the big aveiros which were until this point big separations between you and Hashem, are now removed and no longer serve as mechitzos of division between you and Hashem.
This is what Chazal mean that by saying the Shema Yisrael properly by making spaces in between words, Hashem similarly makes spaces in your aveiros by breaking up the larger and severe ones into smaller and less severe ones. In this manner, Gehenim becomes cooler because the larger aveiros which needed cleansing and tikkun with a very hot fire can now be corrected with a cooler fire. If one continues to break up the Shema then the domino effect takes place in that his now smaller aveiros have become even smaller. As the process is repeated over many times one can begin to feel once again the geshmak in mitzvos and learning Torah, and form a meaningful relationship with Hashem like never before.

With this explanation, we can answer the contradiction in the words of Chazal. It is true that if the only zechus one has is the reading of the Shmah, that alone would suffice to serve as a protection of not being wiped out in the battlefield. However, this reading of the Shemah must be fulfilled in its proper fashion with spaces and breaks between the words. To trigger this segulah of protection, the reciting of Shemah must be a labor of love. This requirement can be derived from the word אהבה which is a condition in this protection plan as the nusach of the kedusahs Mussaf says פעמים באהבה שמע אומרים and at the end of the Vehu Rachum tefillah וחן אם המיחדים שמך פעמים בכל יום תמיד באהבה ואומרים שמע ישראל. With a labor of love, one doesn’t rush through it as if it is a burden and get it over as quickly as possible. On the contrary, with love one cherishes every word individually, gift-wrapping it to the best of his ability.
Because of such a compounded amount of disciplined readings, Hashem takes the aveiros and mirrors your actions by also breaking them into smaller and smaller pieces until there is nothing really tangible left, for one had already done teshuvah on them. So even if the has no other zechusim, the Shema itself is a guarantee that he will be protected in the battle. When the Torah describes the soldier who must return home and not fight, he is described as one who has the aveiros in his hand עבירות שבידו. This means that the aveiros are still tangible because he did say Shemah properly and the aveiros remain in their original sizes and severity without one becoming inspired to do teshuvah on them. The large aveiros hold back a person from doing teshuvah because he has not yet downsized the separations that exist between him and Hashem.

Our generation is one that constantly seeks segulos of every sort sometimes at the expense of self-growth. Be fully aware that it is our Chazal and not some organization, who are revealing to us here a segulah that works. I guarantee that if one begins to say the words of Shemah as if he was counting 100 dollar bills he will feel that a load of separation between him and Hashem is lightened with every precise reciting. It is very possible that during one’s lifetime one never missed saying the Shema even according to the Magen Avraham’s zman which is a great feat. However, with all the invested effort and diligence of reciting the Shemah at the exact time, it is still very possible that this same person does not possess even one  Shemah with a Lechatchilah desirable format. The time was right but the pronunciation of its words was shabby and sloppy.
Chazal say that the 248 words of Shemah correspond to the 248 limbs in one’s body. Each limb is separate and distinct from one other with a specific function. When we overrun words with one another we are mixing up our bodily functions creating within ourselves chas veshalom a non-healthy state in our physical and spiritual well – being. Twice a day we have the opportunity to change our lives and our relationship with Hashem for the better. You can never experience this great segulah if at every recital you always let go of the reins that control your body and middos. By doing so, you become a reckless driver pushing a 100 miles per hour in a speed zone of thirty miles. Your vision is impaired as if you are drunk which unfortunately can cause harm and damage to you and to others. Each word of the Shemah is a living world by itself and because of your zip reading, you crash into words making them meaningless and lifeless. Don’t lose this incredible window of opportunity gifted to us twice a day, one that will tremendously affect us both in this world and the next.

The punishment of galus is stated in the second parsha of Shmah ואבדתם מהרה you will be lost and banished swiftly from Eretz Yisrael. Within the galus curse of these two words there also lies the explanation of why we went into galus. These two words can be read as advice from the Torah “to lose the hastiness”. Yisrael had aveiros and yet they were not aroused to do teshuvah because they read the parshiyos of Shema too hastily without making the proper breaks. If we would have rid and lost the מהרה by reciting the Shemah properly, we wouldn’t have gone into galus. We can bring back the state of geulah by reciting the Shemah slowly and meticulously and fulfill the advice of the Torah of ואבדתם מהרה and thereby reverse the curse of ואבדתם מהרה the swift blow of galus.
Shabbos which is the day of menucha, the receiving of an extra neshama, a day when there is no rushing to go to work, is a day when the tikkun of losing the mehairah can easily take place and be achieved (Shulchan Aruch 301). On Shabbos even the Shemah can now be said with menucha and kedusha. The Chazal say that Shabbos at Kiddush one can rectify the swiftness of the week (Shabbos 112). This is why we find that the gematriah of ואבדתם מהרה equals שבת. Let’s make it happen and bring on the final geulah now.