Reference for Shabbat 246:9
מאי התירו וחזרו והתירו וחזרו והתירו
and a small table-knife. Then<span class="x" onmousemove="('comment',' When they saw that the people became more strict in Sabbath observance. ');"><sup>16</sup></span> they permitted [other articles], and they permitted again [still more], and they permitted still further, until they ruled: All utensils may be handled on the Sabbath except a large saw and the pin of a plough. What is meant by 'then they permitted [other articles], and they permitted again [still more], and they permitted still further'? — Said Abaye: [First] they permitted an article whose function is for a permitted purpose, provided it was required for itself;<span class="x" onmousemove="('comment',' I.e., when it was required for use, but not when its place was required. ');"><sup>17</sup></span>