Rav Yisrael Najara (c. 1555- c. 1625) composed a work entitled Keli Mahazik Beracha, a compendium of different passage that highlight the importance of reciting Birkat Ha’mazon with proper Kavana (concentration). In this work, he tells the story of a Sadik who once hosted a person in his home, and after the meal, the guest recited Birkat Ha’mazon very rapidly. But when the guest reached the blessing for the host, he recited the blessing loudly, slowly and with emotion, as an expression of his gratitude for the host’s gracious hospitality.
After he finished, the Sadik turned to him and said, "You just caused the Shechina a great deal of distress."
The guest was stunned. "Why?" he asked.
The Sadik explained that when it came time to thank the host, the guest recited the text slowly and with a great deal of concentration – as well he should – but during the rest of Birkat Ha’mazon, when he was thanking Hashem, he rushed through the text, mindlessly mumbling the words.
"You showed greater respect to a human being than to G-d," the Sadik said, "and so this Birkat Ha’mazon was not accepted."
When we recite Birkat Ha’mazon, we are giving thanks to Hashem for the many blessings He has given us and continues to give us. When we thank somebody who has done us a great favor, we ensure to do so clearly and enthusiastically. All the more so, then, when we thank Hashem, we should certainly do so in an appropriate manner, slowly and with concentration.
The Yabetz (Rav Yaakob Emden, 1697-1776) observed that some words in the Torah have greater Mazal ("luck") than others, and he quipped that in the verse, "Ve’achalta Ve’sabata U’berachta" ("You shall eat, you shall be satiated, and you shall bless"), the words "Ve’achalta Ve’sabata" have much greater Mazal than "U’berachta." People devote a lot of time and emotion to eating and experiencing satiation, but far less so to "U’berachta" – blessing and thanking Hashem through the recitation of Birkat Ha’mazon.
Let us try to reverse this tendency, and ensure to recite Birkat Ha’mazon slowly and with concentration, expressing the gratitude we owe Hashem for all that He gives us each and every day.