法華義疏 2.210

2.210

將彼顯此明一乘之相也。亦名最後施，如須太挐太子施物已窮，最後唯餘自所乘車，有人乞之，菩薩亦捨。

It is using that to reveal this, clarifying the marks of the ekayāna. It is also called the ultimate giving. For example, when Prince Sudāna had exhausted his possessions through giving, in the end only the carriage he rode remained; someone begged for it, and the bodhisattva relinquished that as well.