This brings us to Yaakov’s lesson: This work must be performed “with all his strength”.
It is not sufficient to be merely “precise with regard to time” — avoiding the pitfall of “tarry{ing} slightly here and there.” A person might justify pausing briefly from the employer’s work to pursue personal perfection (“filling one’s belly,” gaining additional Torah understanding, and the like). But such small interruptions {accumulate and ultimately} cause him to spend “the entire day — the whole ‘day to do them’ — in deceit.”
But more is required. “One is obligated to work with all his strength,” engaging the full spectrum of his soul-faculties.
A Jew might assume that within the protected environment of Torah and prayer, his Divine service consists of his intellect — the comprehension of Torah — and his emotions — “What is the service of the heart? Prayer” — worship through love and awe.
However, when venturing into the street to transform the world into G-d’s dwelling place, the work would seem to require primarily action, with service rooted only in kabbalas ol.
The instruction teaches otherwise: creating a dwelling for Him in the lowest realms obligates one to employ all his strength — not only his practical faculties, but also his inner ones: his intellect, his emotions, and even his encompassing powers, his will and pleasure.
One might mistakenly think this is merely an enhancement of the mitzvah, for the act of creating the dwelling appears to depend chiefly on deed. The instruction clarifies: It is an absolute obligation — without it, one commits theft (neglect) of the employer’s work.
Although the technical “definition of work” — creating His dwelling in the lower realms — could be fulfilled through action alone, for it to qualify as the Employer’s work, the service must be performed with all one’s strength. A Jew must truly recognize that his entire purpose is to fulfill the mission entrusted to him by Hashem — to make for Him a dwelling place below. As a worker, his very person belongs to the Employer — the Holy One, blessed be He. Consequently, he performs the employer’s work with all his strength.
Through a Jew serving with all the faculties of his soul, he “receives his reward even in this world,” reaching a state of “וַיִּפְרֹץ הָאִּישׁ מְאֹד מְאֹד” {“and the man became prodigiously wealthy”} — with a double expression of “meod,” signifying boundlessness beyond all limitations. Only through service in this world does one attain the true “meod.”
From sichos delivered on Shabbos Parshas Vayeitzei, 5719 (1958)