Reference for Moed Katan 25:11

מתקיף לה רב פפא אלא מעתה בנין לישתרי שכן כותל הגוהה לרה"ר סותר ובונה כדרכו מפני הסכנה

Now, if you presume that 'earning-jobs' are allowed<span class="x" onmousemove="('comment',' During the festival week.');">²⁰</span> where one has not [enough] to eat, then also all [other] work should have been allowed here,<span class="x" onmousemove="('comment',' On the fourteenth of Nisan, instead of limiting the permission to three crafts only, because there may be other craftsmen who may be in need of money for food. But, as there is no mention of such a contingency there, it shows that even in such a case, unnecessary odd 'earning-jobs' may not be given in the festival week.');">²¹</span> because 'earning-jobs' are permitted<span class="x" onmousemove="('comment',' During the festival week.');">²⁰</span>

Jastrow