Thomas Aquinas

Second, he shows the security of the rebuilt city: and your gates shall be open continually, because the fear of their enemies has ceased, and out of necessity for those who come to worship in Jerusalem; and this is so that the strength of the Gentiles may be brought to you. Mystically: gates, ministers who lead others into the faith and the Church, prepared, in prosperity and adversity, to receive converts to the faith: the gates thereof shall not be shut (Rev 21:25).

Commentary on Isaiah ↗