You spoke of my true merits very well. {Truly it is as he has said}

The Thus Come One’s wisdom and meritorious virtues enabled him to preach the path of the three first and the One later, and Kāśyapa himself has spoken of it by taking up a parable. What he has said shows that he has attained to the Sage’s meaning. Hence, in sanctioning it, [the Buddha says], “Truly it is as he has said.”

In reality, however, I have more merits. They are innumerable, asaṃkhya.

What has been said (by Mahākāśyapa and others) is “true” and real because it relates to the region of the One. Now this passage deals with the boundlessness of the region of the One. The boundlessness of the region of the One, unexhausted for many kalpas, broadly verifies [the theme] that the transformative teaching of the three is [identical with] that of the One; how, then, can there be any mistake?

I expound all teachings with expedients by my wisdom in order to lead all living beings to the stage of knowing all things. I know what region a living being will be taken to by what teaching, and what a living being has deep in his mind. I am not hindered by anything in knowing all this. I know all things clearly, and show my knowledge of all things to all living beings.

What is explicated here is how [the Buddha] has reached the state of All-Knowledge (sarvajñā): first, by investigating thoroughly the profound intent of the dharmas; and second, by knowing where living beings’ thoughts tend to go. Because he knew that medicines help regulate diseases, he took them, which led him to bring depravities and calamities to an end without fail, finally attaining to the All-Knowledge.
Tao-sheng Commentary on the Lotus Sutra, p242