An infant may be circumcised [either] on the eight, ninth, tenth, eleventh, or twelfth [day], not earlier not later. How is this? In the normal course, [he is circumcised] on the eight; if he was born at twilight, he is circumcised on the ninth; [if he was born] at twilight on the eve of the Sabbath, he is circumcised on the tenth; [if] a festival [falls] after the Sabbath, he is circumcised on the eleventh; [in the case of] the two festival days of Rosh Hashanah, he is circumcised on the twelfth. A sick infant, we may not circumcise him until he recovers.