Another interpretation: great is circumcision, for it is weighed as equal to the entire Torah, as it is said, "For according to these words I have cut a covenant with you." "Walk before Me and be whole" (written in remez 50).
Circumcision Weighed Against the Whole Torah
Yalkut Shimoni on Torah 81:4
דָּבָר אַחֵר, גְּדוֹלָה מִילָה שֶׁשְּׁקוּלָה כְּכָל הַתּוֹרָה כּוּלָּהּ שֶׁנֶּאֱמַר, "כִּי עַל פִּי הַדְּבָרִים הָאֵלֶּה כָּרַתִּי אִתְּךָ בְּרִית". הִתְהַלֵּךְ לְפָנַי וֶהֱיֵה תָמִים (כָּתוּב בְּרֶמֶז נ').