Musar for Nedarim 63:8
אמר רב יהודה אמר רב בשעה שאמר לו הקב"ה לאברהם אבינו התהלך לפני והיה תמים (בראשית יז, א) אחזתו רעדה אמר שמא יש בי דבר מגונה כיוון שאמר לו ואתנה בריתי ביני ובינך (בראשית יז, ב) נתקררה דעתו
Another version [of Rabbi's teaching] is this: Great is circumcision, for it counterbalances all the [other] precepts of the Torah, as it is written, For after the tenor of these words I have made a covenant with thee and with Israel.<span class="x" onmousemove="('comment',' Ex. XXXIV, 33. After the tenor of these words is taken to refer to all God's precepts; by a 'covenant', 'circumcision' is understood; thus the two — all God's precepts and circumcision — are equated. Rashi appears to have the following reading: As it is written, Behold the blood of the covenant, which the Lord hath made with you concerning all these words (Ex. XXIV, 8); and it is also written. And I will mike my covenant between me and thee (Gen. XVII, 2). Just as 'covenant' in the latter verse refers to circumcision, so also in the former; whilst the end of that verse, 'concerning all these words', shews that circumcision is equal in importance to 'all these words', i.e., all God's commandments. ');"><sup>14</sup></span> Another version is: Great is circumcision, since but for it heaven and earth would not endure, as it is written, [Thus saith the Lord,] But for my covenant by day and night,<span class="x" onmousemove="('comment',' V. p. 93, n. 8. ');"><sup>15</sup></span>