Reference for Shabbat 274:6
מל ולא פרע: ת"ר המל אומר אקב"ו על המילה אבי הבן אומר אקב"ו להכניסו בבריתו של אברהם אבינו העומדים אומרים כשם שנכנס לברית כך יכנס לתורה לחופה ולמע"ט
IF ONE CIRCUMCISES BUT DOES NOT UNCOVER THE CIRCUMCISION. Our Rabbis taught: He who circumcises must recite: '… Who hast sanctified us with Thy commandments, and hast commanded us concerning circumcision.' The father of the infant recites, '… Who hast sanctified us with Thy commandments and hast commanded us to lead him into the covenant of our father Abraham.' The bystanders exclaim, 'Even as he has entered the covenant, so may he enter into the Torah, the marriage canopy, and good deeds.' And he who pronounces the benediction recites: '… Who hast sanctified the beloved one<span class="x" onmousemove="('comment',' Rashi refers this to Isaac; Tosaf. to Abraham. ');"><sup>4</sup></span>