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״ואכלת ושבעת וברכת את ה׳ אלהיך״
One must focus on this פסוק because it is the secret source of blessings

If people sanctify themselves by saying Birchas Hamazon properly, "the food they eat will heal them of their illnesses."

Birchas Hamazon contains all the letters of the Alef Beis except for the letter ף. This teaches us that those who say Birchas Hamazon with proper concentration will be spared from the angels of אף,שצף,קצף,אנף- anger, wrath, fury, and ire.

Birchas Hamazon holds incredible powers. Those who bentch with kavanah can ask Hashem for anything they need.

I have a tradition from my teachers that anyone who is careful to fulfill the mitzvah of Birchas Hamazon is assured that he will find his livelihood in an honorable fashion his entire life.

Rav Chaim Vital said that in reward for fulfilling the mitzvah of Birchas Hamazon, Hashem will open the trove of bounty for you and you will always be sustained through His generous Hand.

If someone always says Birchas Hamazon out loud, he will be granted a long life.

Saying Birchas Hamazon from a siddur or bentcher with kavanah is מסוגל for having children and grandchildren who fear Hashem and are תלמדי חכמים.

Boaz was very careful to say Birchas Hamazon with kavanah and in that זכות, Hashem sustained the entire בני ישראל during the years of the famine.

The Chida writes that saying Birchas Hamazon out loud and with joy will likely cause one to become wealthy, as it says in Mishlei (10:22) "Hashem’s blessing makes one wealthy..."

The Steipler said that children who are raised in a home where the mother says Birchas Hamazon out loud will have Heavenly protection from illnesses and accidents.

The Maharil Diskin advised childless women to say Birchas Hamazon with kavanah and with a bentcher, adding that doing so can ward off terrible punishments.

A woman came to Rav Shach after being married for several years without having children. He told her to make a kabbalah to always say Birchas Hamazon from a bentcher. Within a year, she gave birth to a healthy child.

Anyone who recites Birachas Hamazon is blessed through it

ואכלת ושבעת - “blessing” is in the “bread”