瑜伽師地論略纂 7.80

7.80

第七段，城者，內以攝持，外有捍御，內攝四法，外御信解，故喻城。　「相應善法二種心城」者：一、善說法；二、毘奈耶。

In the seventh section, a "city" gathers and holds internally, and fends off externally; internally it gathers the four dharmas, and externally it defends against faith and conviction, hence the metaphor of a city. As for the "two kinds of mind-cities of conjoined wholesome dharmas": first, the well-spoken Dharma; second, the Vinaya.