Rebbe Zev of Zhitomir zt'l was once in an inn and saw someone eating without a brachah. Reb Zev told him that there are neshamos in food. Sometimes, a neshamah waits for years for a tikkun, and if a person says a brachah over food, the neshamah can go up to Gan Eden. Reb Zev added, "And at times, the neshamah in food is the neshamah of your own relative, perhaps even of your father or mother." The man hit his forehead with his hand and shouted, "Today is my father's yahrzeit!"
For many reasons, it is important to say brachos with kavanah. There are kelipos, impurities, in food, that can draw a person down. And, in contrast, there is kedushah, holy sparks in food that can elevate the person. A primary factor determining whether he will go up or down from the meal is how he says the brachos over the food.
Reb Chaim Vital zt'l writes, "My teacher, the Arizal, told me that attaining ruach hakodesh depends on the degree of kavanah one has when he makes brachos on food. When the brachos are said with kavanah, it destroys the kelipos, and the food is pure to receive holiness. The Arizal warned me about this a lot... A person must be extremely careful with brachos over foods because the person becomes holy from these brachos, as it says (Tehillim 40:9), מעי בתוך ותורתך, 'Your Torah is in my stomach.' A divine spirit comes to the person."
When one makes an המחיה על, he says the phrase, ובטהרה בקדושה עליה ונברכך, "We will bless You in the land with holiness and with purity..." We don't mention kedushah and taharah in המזון ברכת. Why is that? Rebbe Aharon of Belz zt’l explains that this is because when we eat bread, we first wash our hands, and the entire mannerism of eating is generally with kedushah and taharah. Therefore, we don't need a reminder in the brachah that we should eat with holiness and purity because, generally, that is how the meal will appear. However, mezonos is often eaten in haste. When someone is hungry, he grabs a mezonos and eats it. He doesn't wash his hands first. He might forget to eat with purity and holiness. Therefore, Chazal established that the brachah acharonah should remind us to eat these mini-meals with kedushah and taharah.
Tzaddikim of the Bobov dynasty sought to say המחיה על every day so they could say the words ובטהרה בקדושה עליה ונברכך.
