Smiling gently, the master stopped the traveler and said:

They say that a knotgrass eater gets used to its sharp taste, and an insect living in a honey bucket does not smell its offensive odor. Affected by surroundings, people tend to lose their sense of judgement. So you take a good word for a bad one, call the slanderer of the True Dharma a holy man, and suspect the true teacher of being a false one. You are utterly confused and have committed a grave sin. Now listen carefully, I will explain in detail what caused your confusion.

Śākyamuni Buddha’s lifetime preachings in five periods were done in sequence and proper use of provisional and true teachings. He began with provisional doctrines which were easier to understand by less prepared people with lesser capacity. Gradually, the Buddha preached doctrines progressively closer to the truth and more difficult to comprehend, as the listeners became better prepared, until finally He revealed the ultimate truth in preaching the Lotus Sūtra.

Risshō Ankoku-ron, Treatise on Spreading Peace Throughout the Country by Establishing the True Dharma, Writings of Nichiren Shōnin, Doctrine 1, Pages 124-125