Reference for Rosh Hashanah 65:1

ואין חותכין אותו בין בדבר שהוא משום שבות ובין בדבר שהוא משום לא תעשה: משום שבות מגלא לא תעשה סכינא

IT MUST NOT BE SHAPED EITHER WITH AN IMPLEMENT THE USE OF WHICH IS FORBIDDEN ON ACCOUNT OF SHEBUTH OR WITH ONE THE USE OF WHICH IS FORBIDDEN BY EXPRESS PROHIBITION.' An instrument the use of which is forbidden on account of shebuth' - as for instance, a sickle.<span class="x" onmousemove="('comment',' To cut ordinary articles with a scythe or sickle on Sabbath is not regarded legally as 'work' because the implement is not being used for its proper purpose. The Rabbis, however, forbade it on account of shebuth.');">¹</span>

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