“Man lives” that it is specifically bread which causes a prolonged connection between the Neshomoh and the body. [I.e sustains the person]. In other words, when a person actively does deeds in his portion of the world, this adds something to and causes an elevation within that person performing those deeds that he becomes a ‘מְׁהַלֵׁךְ’ in the way of:
Bread and the Connection of Body and Soul
There is a Possuk (in Devorim 8:3) that states: וַיְׁעַנְׁךָ וַיַרְׁ עִׁבֶךָ וַיַאֲכִׁלְׁךָ אֶת־הַמָן אֲשֶר לֹא־יָדַעְׁתָ וְׁלֹא יָדְׁעוּן אֲבֹתֶיךָ לְׁמַעַן הוֹדִׁיעֲךָ כִׁי לֹא עַל־הַלֶחֶם לְׁבַדוֹ יִִֽׁחְׁיֶה הִָֽאָדָם כִׁי עַל־כָל־מוֹצָא פִִֽׁי־ה׳ יִׁחְׁיֶה הָאָדָם: “And He afflicted you and let you go hungry, and then fed you with Manna, which you did not know, nor did your forefathers know, so that He would make you know that man does not live by bread alone, but rather by, whatever comes forth from the mouth of HaShem does man live.”
Just as food sustains the connection between the body and the Neshomoh, (because if someone was to not eat for a few days his Neshomoh would leave his body). So too the Divine spark that is inside the food (Which is the source of the bread's vitality) is what keeps the bread in existence, keeping the elevated spiritual element of the bread together with the lowly physical element of the bread.
Refining One's Portion in the World
Everyone has a part of the world that he needs to refine. As it says in Hayom Yom for Ellul 3: Whoever has faith in individual Divine Providence knows that "Man's steps are established by Hashem, that this particular Neshomoh must purify and improve something specific in a particular place. For centuries, or even since the world's creation, that which needs purification or improvement waits for this Neshomoh to come and purify or improve it. The Neshomoh also has been waiting ever since it came into being for its time to descend, so that it can discharge the tasks of purification and improvement assigned to it."
Becoming a Mehalech
He becomes a Mehalech: lit. a Goer. As in the Possuk (Zecharia 3:7) כֹה־אָמַר ה׳ צְׁבָאוֹת אִׁם־בִׁדְׁרָכַי תֵלֵךְ וְׁאִׁם יֵׁלְׁכוּ מֵׁחַיִׁל אֶׁל־חָיִׁל “They will go from strength to strength”.
