Reference for Shabbat 231:1
שאין זה מקומה ר' אומר לא מן השם הוא זה אלא מפני שספר חשוב הוא בפני עצמו
that this is not its place. Rabbi said: It is not on that account,<span class="x" onmousemove="('comment',' Lit., 'designation'. ');"><sup>1</sup></span> but because it ranks as a separate Book. With whom does the following dictum of R. Samuel b. Nahmani in R. Jonathan's name agree: <i>She [Wisdom] hath hewn out her seven pillars</i>:<span class="x" onmousemove="('comment',' Prov. IX, 1. ');"><sup>2</sup></span> this refers to the <i>seven</i> Books of the Law? With whom? With Rabbi.<span class="x" onmousemove="('comment',' Since that section is a separate Book, the portions of Numbers preceding and following it are also separate Books; hence there are seven in all. ');"><sup>3</sup></span>