Commentary for Berakhot 55:2

תנא אותו היום סלקוהו לשומר הפתח ונתנה להם רשות לתלמידים ליכנס שהיה ר"ג מכריז ואומר כל תלמיד שאין תוכו כברו לא יכנס לבית המדרש

It has been taught : That same day, they removed the doorkeeper [of the College] and permission was granted to the disciples to enter ; for Rabban Gamaliel had issued a proclamation: "A disciple, who is not inwardly the same as outwardly, will not be allowed to enter the House of Study."

Abraham Cohen Footnotes to the English Translation of Masechet Berakhot