妙法蓮華經玄義 10.195

10.195

佛為求三乘人說三乘法，然聞因緣者，即是聲聞。辟支佛出無佛世，但現神通，默無所說，故結集經者集為二藏也。依經判教，厥致云爾。

The Buddha preached the tri-yāna dharma for persons seeking the tri-yāna, but those who hear causes and conditions are śrāvakas. Pratyekabuddhas appear in eras without a buddha; they merely display supernatural powers and remain silent without preaching. Therefore, the compilers of the sūtras compiled them into two piṭakas. Classifying the teachings by relying on sūtras, the principle is just like this.