四分律行事鈔資持記 1.786

1.786

示名相中。初投重來，兩番破外。受竟反還，即是破內。又須定約具戒為言；若受十戒，破不成難。彼下，出障所以。

Under "explaining the names and marks": First joining and then coming again is twice destroying the external. Turning back after receiving the precepts is destroying the internal. Furthermore, one must definitely speak in terms of the complete precepts; if one only receives the ten precepts, breaking them does not constitute an obstacle. From "That" onward, he shows the reason for the obstacle.