There is nothing secret or esoteric in the following. It is the completely OPEN TEACHING of the Lotus Sutra: you can become the "Buddha in this lifetime." Here are two quotes.
"I (Shakyamuni Buddha) am always thinking: how shall I cause all the living to enter the highest path and quickly acquire the body of a Buddha"
The above is at the end of the 16th chapter, and below is the end of the 21st chapter.
"This man (i.e., follower of this sutra), while working in the world, can disperse the gloom of the living, and cause innumerable bodhisattvas to ultimately abide in the Buddha Vehicle. He who accepts and upholds this sutra assuredly will attain the Buddha Way. Of this have no doubt."
This accounts for Dengyo Daishi's assertion that the Lotus Sutra and the Mikkyo are equivalent in their result.