The Pnei Menachem (Parshat Ekev תשנב) quotes his father, the Imrey Emes Zatzal , who taught that through Birkat Hamazon with kavannah we can lift up eating which was not done properly, but if a person doesn't bless properly, he will be judged for his improper eating.
The holy and pure Maggid Memezeritch would remind his students to be careful to bench with kavannah even more then for tfillah, since tfillah is derabbannan (rabbinical), while Birkat Hamazon is DeOrayta (from the Torah), but if one has proper intention in eating and drinking, he causes unifications above, and love and brotherhood, and all of the spiritual worlds send down shefa and blessing to the lower worlds"
Blessing Out Loud:
The Deebart Shlomo of Rav Shlomo Milutzk (Lech lecha):
In the writings of the Arizal it's written that we must say Birchat Hanehenin in a loud voice. For in every thing, there is a life force from Hashem, as it's written, in Nechemia 9:6 "For you bring life to everything". But matters are in physical kelippot shells, and this is called the sitra achra, for the shells and physicality bring a person to taavah and cheemood for the desires of this world. But a wise man can distinguish between the taste of the spark of the creator which dwells within the food, and he can attach himself to the creator of the world through this.
And the main way we remember this is through blessing, through blessing and praising Hashem, WHO CREATED THIS THING AND BRINGS LIFE TO IT, WHICH IS THE VITALITY AND THE TASTE AND THE SMELL OF THE Matter which dwells in this matter. and this is the meaning of the teaching of Chazal (Brachot 35a( that one who benefits from this world without a Bracha is as if he has stolen from Hashem. And this is what the Arizal writes takes away the Sitra Achra which means that he seperates the phsycial shells which surround spirituality within it, and attaches himself to the inner essence.
The Chida writes that a segullah for Parnassah is to bless Birkat Hamazon with a voice and with joy, and he brings a hint to this from the verse in Mishlei 10: 22 "The blessing of Hashem will make rich".
The Deebart Shlomo of Rav Shlomo Milutzk (Lech lecha):
In the writings of the Arizal it's written that we must say Birchat Hanehenin in a loud voice. For in every thing, there is a life force from Hashem, as it's written, in Nechemia 9:6 "For you bring life to everything". But matters are in physical kelippot shells, and this is called the sitra achra, for the shells and physicality bring a person to taavah and cheemood for the desires of this world. But a wise man can distinguish between the taste of the spark of the creator which dwells within the food, and he can attach himself to the creator of the world through this.
And the main way we remember this is through blessing, through blessing and praising Hashem, WHO CREATED THIS THING AND BRINGS LIFE TO IT, WHICH IS THE VITALITY AND THE TASTE AND THE SMELL OF THE Matter which dwells in this matter. and this is the meaning of the teaching of Chazal (Brachot 35a( that one who benefits from this world without a Bracha is as if he has stolen from Hashem. And this is what the Arizal writes takes away the Sitra Achra which means that he seperates the phsycial shells which surround spirituality within it, and attaches himself to the inner essence.
The Chida writes that a segullah for Parnassah is to bless Birkat Hamazon with a voice and with joy, and he brings a hint to this from the verse in Mishlei 10: 22 "The blessing of Hashem will make rich".
The Rebbe Miklauzenberg tells a story brought down by the Shefa Chayim.
Shalom Eliezer, as a youth sat by the table of his holy father (the Divrey Chayim) and did a fast Benching. Afterwards the holy Old man said, today you didn't say Birkat Hamazon. I responded: i was relying upon you to raise up my Birkat Hamazon. The Holy Old man responded: If one doesn't Bench properly so than it's possible for the tzaddik to raise up his Benching. But since you didn't Bench at all, there was nothing to raise up!
Shalom Eliezer, as a youth sat by the table of his holy father (the Divrey Chayim) and did a fast Benching. Afterwards the holy Old man said, today you didn't say Birkat Hamazon. I responded: i was relying upon you to raise up my Birkat Hamazon. The Holy Old man responded: If one doesn't Bench properly so than it's possible for the tzaddik to raise up his Benching. But since you didn't Bench at all, there was nothing to raise up!
Rav Mordechai Masniut would raise his hands to the heavens , and bless Birkat Hamazon with so much Kavannah that he wouldn't notice guests who would come to visit him...