Reb Yisroel Jacobson relates:
Reb Gershon Henich Eichhorn was a Chossid of the Previous Rebbe. He was a talmid chochom (Torah scholar), and after moving to America he would deliver a regular class in Talmud in the Bnei Adass Yisroel Shul. However, the rest of the week he would do back-breaking work in a laundromat for a wage of $30 per week. When the Previous Rebbe arrived in America, Reb Gershon Henich was appointed as fundraiser for Tomchei Temimim (the Chabad Yeshivah) for which he went on to become very active. When Reb Itcheh Der Masmid asked the Previous Rebbe whether to accept Reb Gershon Henich into the Chabad office, the Previous Rebbe agreed with pleasure, and said, “If he will toil for the Chabad organization like he works in the laundromat, it will be beneficial for both sides.”
Zikaron Livnei Yisrael, p. 119.
Lesson: One should take the same energy that one uses to satisfy one’s material needs, and invest it in holiness. This is a way of assessing whether one is toiling sufficiently in spreading Torah and Chassidus.
Comment: This is really the same idea that the Previous Rebbe expresses in maamar of Basi Legani, which we learn in preparation for 10 Shevat, where he writes that one should take the Animal Soul’s natural passion for the physical and transform it, using it to serve Hashem.