法華玄論 6.128

6.128

問：初成道時實有三乘根性，故云「長者諸子若十二十或至三十」。若爾，三乘教為三根人，何得於一說三為二乘人耶？

Question: At the initial attainment of the way, there were truly the dispositions of the three vehicles; hence it says: "The elder's children, whether ten, twenty, or up to thirty." If so, the teaching of the three vehicles was for persons of the three faculties; how could teaching three based on the one be only for persons of the two vehicles?