Reference for Rosh Hashanah 65:2

השתא משום שבות אמרת לא לא תעשה מיבעיא זו ואין צריך לומר זו קתני:

'An implement which is forbidden by express prohibition' - as for instance, a knife. Seeing that you disallow an implement prohibited on account of shebuth, need you mention one disallowed by express prohibition?<span class="x" onmousemove="('comment',' The sanction for which is Pentateuchal and not merely Rabbinical.');">²</span>

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