大方廣佛華嚴經隨疏演義鈔 21.19

21.19

疏「便能」下，第二約果城說三義。果由理行成，故云便能。即契果位三德，為涅槃城之三義矣。

Regarding the Commentary's "[one] is then able to..." downward, this secondly explains the three meanings in terms of the city of fruit. The fruit is accomplished through principle and practice, hence it says "is then able to." That is, it accords with the three virtues of the stage of fruit, constituting the three meanings of the city of nirvāṇa.