Reference for Yevamot 144:1
אין נימולין אלא ביום שלא בזמנו נימולין ביום ובלילה מאי לאו בהא קמיפלגי דמר סבר משוך דאורייתא ומר סבר משוך דרבנן
children may be circumcised in the daytime only; and if not at the proper time they may be circumcised both by day and by night,<span class="x" onmousemove="('comment',' Tosef. Shab. XVI. ');"><sup>1</sup></span> Do they not differ on the following principle: While one Master<span class="x" onmousemove="('comment',' The first Tanna who restricts the time of the circumcision to the day only. ');"><sup>2</sup></span> is of the opinion that the circumcision of a <i>mashuk</i> is a pentateuchal law, the other Master<span class="x" onmousemove="('comment',' R. Eleazar b. Simeon. ');"><sup>3</sup></span> is of the opinion that the circumcision of the <i>mashuk</i> is only a Rabbinical ordinance?<span class="x" onmousemove="('comment',' Hence he permits its performance during the night also. Would then R. Huna's ruling agree with the view of one Tanna only! ');"><sup>4</sup></span>