Reference for Shabbat 263:19

רב אחא בר יעקב אמר אמר קרא שמיני שמיני אפילו בשבת

R. Johanan said: Scripture saith, in the [eighth] day, 'in the day' [implying] even on the Sabbath.<span class="x" onmousemove="('comment',' This is according to the Rabbis. R. Eliezer, as stated supra, utilizes this in respect of the preliminaries. Hence he holds that circumcision itself is a traditional law, whilst he learns that life saving is permitted from a Scriptural verse (Yoma 85b). ');">¹⁷</span>

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