釋氏要覽 1.100

1.100

史云。正者政也。自正正人。克敷政令故。蓋以比丘無法。若馬無轡勒。漸染俗風將。乖雅則故。擇有德望者。以法而繩之。令歸乎正故云僧正。此以偽秦僧[(丰*力)/石]。為始也。至梁普通六年勅法雲。為大僧正（此加大字）。

The History says: Rectitude (zheng) means governance (zheng). One rectifies oneself to rectify others and can thus propagate governmental orders. For if monks have no rules, it is like horses without bridles: gradually tainted by worldly customs, they would contravene the refined norms. Therefore, those of virtue and prestige are selected to regulate them by law and make them return to rectitude; hence the name sengzheng (monk rector). This began with Sengqie under the illegitimate Qin. Coming to the sixth year of the Putong era of the Liang, an imperial decree appointed Fayun as the Grand Monk Rector (da sengzheng; adding the word 'grand').