Birkas HaMazon
It states in this week's parashah (8:10), ואכלת אלקיך 'ה את וברכת ושבעת, "You will eat and you will be satisfied and bless Hashem, your G-d." This refers to the mitzvah of benching after eating bread.
Many brachos come from being careful with birchas hamazon. The Chinuch (Mitzvah 430) writes, "I learned from my teachers that whoever is careful with birchas hamazon will have parnassah in an honorable manner his entire life."
The Zohar (vol.2 218.) writes, "Birchas hamazon is precious to Hakadosh Baruch Hu... When one eats and is satisfied, and benches with joy, Hashem will bestow blessings on him with joy and generously. Therefore, don't bench with sadness, only joyfully."
The Chida writes that since it is important to say birchas hamazon with joy, therefore, One should eat something that brings him joy so that he will bless Hashem with joy. Blessing Hashem with joy and with a loud voice is a segulah for wealth. This is alluded to in the pasuk (Mishlei 10:22) עֶצֶב יוֹסִף וְלֹא תַעֲשִׁיר הִיא 'ה בִּרְכַּת עִמָּה, "The blessing of Hashem brings riches..." 'ה בִּרְכַּת refers to birchas hamazon because that is the only brachah that is a d'Oraysa, from the Torah. This is the reason it is called 'ה בִּרְכַּת, "Hashem's brachah". All other brachos are d'Rabbanan. שִירתַעֲש הִיא, this brings wealth. The condition is עִמָּה עֶצֶב יוֹסִף וְלֹא, that he should bench with simchah because this removes the Sitra Achara."
Pele Yoetz (Achilah) writes, "A person must say birchas hamazon בנחת (pleasantly, without rushing), in a loud voice, and with a happy heart. If a person thinks about the words he is saying, it is impossible that he won't be happy. It appears from the Zohar that a person must do everything to get himself to bench with simchah, as it states (Rus 3:7) לִבּוֹ וַיִּיטַב ְּוַיֵּשְׁת בֹּעַז וַיֹּאכַל, and this means that Boaz benched birchas hamazon (with a happy heart)."
The Chareidim (ch.12) writes, "Mitzvas asei to bench birchas hamazon as it states (Devarim 8:10) ושבעת ואכלת אלקיך 'ה את וברכת, "You will eat and you will be satisfied and bless Hashem, your G-d." One must benech בנחת הלב ובשמחת רם ובקול, pleasantly, in a loud voice, with joy in his heart, as it states (Rus 3:7) לִבּוֹ וַיִּיטַב ְּוַיֵּשְׁת בֹּעַז וַיֹּאכַל, "Boaz ate and drank, and his heart was happy," which means he benched Hashem with joy.
Rabbeinu Sadyah Gaon, when he counts the mitzvah of birchas hamazon ('ל מצוה ג"רס), he writes ושבעת ואכלת כח ברון, - which means to bench with joy.
Segulah for Parnassah and Protection
Reb Meir Shapiro (rosh yeshiva of Chachmei Lublin), zt'l, once tested the students of a cheder. Generally, after conducting such a test, Reb Meir Shapiro would give the students a small gift. This time he said, "I wanted to give you a present, only I don't have anything with me. So, I will teach you a segulah instead. If you follow this advice, you will be successful and you will have a peaceful life. Revealing this segulah is my gift to you."
He told them the segulah to say birchas hamazon with kavanah. He quoted the Ba'ch, who says, "Whoever recites birchas hamazaon with kavanah, neither wrath nor destruction will ever befall him." And he shared with them the words of the Chinuch, that "Whoever is careful with birchas hamazon will have parnassah b'kavod his entire life."
He advised them to bench from a siddur and not by heart.
Shimon, one of the students of that cheder, immediately made a kabbalah always to be careful with birchas hamazon. His friends benched quickly and ran out to play while he stayed behind to bench properly. It was challenging, but he didn't want to lose out on the wonderful gift Reb Meir Shapiro gave them – a segulah for a prosperous and peaceful life.
Some years later, the Nazis invaded Poland, and Reb Shimon stood in line for the 'selektzia.' Whoever was short was sent to the left, to the gas chambers and crematoriums. As Reb Shimon stood in line, he prayed the entire time that in the merit of birchas hamazon, he should be saved from 'wrath and destruction (שצף קצףand אף חרון). When it was his turn, he stood on his toes to appear taller, and the Nazi signaled him to the right. He understood that his life was saved in the merit of birchas hamazon.
Soon afterward, Reb Shimon found himself standing in line again. This time, each person had to tell the Nazi at the head of the line what his trade was. Reb Shimon didn't know what he could say. He was only a teenager, and he had never worked before.
Again, he prayed, "In the merit of birchas hamazon, which is mesugal for parnassah, Hashem, please help me and support him." Immediately after he finished his tefillah, the person behind him tapped him on the shoulder and said, "Say that you are a cook and that I'm your helper." When it was Reb Shimon's turn, he said this, and they were both sent to work in the kitchen. Reb Shimon understood that he was being rewarded once again for being cautious with birchas hamazon, which is mesugal for parnassah. Now he was working in the kitchen, where, naturally, there was more food to eat.
Reb Shimon continued to be extremely careful with birchas hamazon. If he felt he wouldn't have enough time to say birchas hamazon properly, he wouldn't eat his bread (indeed, a great mesirus nefesh during the Holocaust, even in his improved position).
Once, a Nazi officer saw Shimon working in the kitchen and asked, "What are you doing here? You look like a young child." "I work here," Shimon explained. "I'm the cook." The officer took Shimon outside, behind the kitchen, gave him a shovel and said, "Dig a ditch here, two meters deep. If it isn't finished in two hours, you will be shot." At that time, the Nazis were building trenches to hide in, in case the Russians would attack them.
However, the task the Nazi gave Shimon was impossible. The ground was covered with heavy rocks, and he was given a small shovel to work with! Furthermore, he only had two hours to finish the job!
Reb Shimon raised his eyes to heaven and said, "I say birchas hamazon with kavanah, which is mesugal to save me from 'wrath and destruction' (קצף שצף and אף חרון). You saved me before, please save me again."
A few moments later, a jeep drove by, filled with Nazis. They saw Shimon trying to dig a ditch with a small shovel. To tease him, they threw vegetables at him. Reb Shimon thought wryly, "I see that in the merit of birchas hamazon, I once again received the blessing of abundance. Now I need the blessings for protection from wrath and destruction as well."
Immediately after this prayer, a jeep with Russian Prisoners of War (POWs) showed up. When they saw all the vegetables scattered around Shimon, they stopped and asked for some. (They were hungry because the Nazis barely fed these prisoners.) With an authoritative voice, Shimon told the Russians, "This is for the kitchen, and not for you. But if you will help me dig a trench here, two meters deep, I will give you the vegetables." The Russians were strong, and they had the right tools for digging. They finished the job in half an hour.
The Nazi returned and saw that the task was completed. He said, "I always knew that your G-d takes care of you. I just didn't realize to what extent." Reb Shimon knew that he was saved once again in the merit of birchas hamazon.
When Reb Shimon came to Eretz Yisrael after the war, he always had parnassah, and he married off all his children honorably. He attributes it to the merit of birchas hamazon.
Additional Teachings on Birchas Hamazon
It says in Shach al HaTorah (a student of the Arizal) that whoever is careful to say birchas hamazon, with kavanah, will not be eaten by worms and insects in the grave. ברוך he writes, is gematriya כרז (announcement). An announcement goes forth from heaven, warning the worms not to eat this person who was careful with birchas hamazon—the blessings (ברכות) of birchas hamazon counter the curse of worms.
Sefer Chasidim (46) writes, "Someone died young, several years before his time. More than a year after his petirah, he appeared to his relative in a dream. The relative asked him, 'How are things for you in the next world?' "I am being judged daily because I wasn't careful to recite birchas hamazon and brachos over foods with kavanah. They tell me that I was eating for my own pleasure." "But doesn’t the judgment in heaven last only twelve months? You were niftar more than a year ago." He replied, "The punishments of the first twelve months were more severe."
