The Dharma which was attained and taught by Sakyamuni is the Universal Truth or Law, which must be acknowledged by every human being. There is only one Truth. However, so that people could understand it better, Sakyamuni expounded the one Truth in various ways, according to the capacities of his listeners. The varieties in Sakyamuni’s teaching show that the Truth is not rigid; rather it is flexible enough to be presented in different forms, according to the circumstances, despite its oneness. This is the reason Sakyamuni’s numerous sutras can be said to compose one and the same teaching. Unfortunately, sectarians, who did not understand the unity of Truth, began to turn these partial truths against each other and vie with each other for superiority. Their teachings, diverse as they may appear, are still united in the single teaching of the Buddha. The concept of the unification of doctrines is the very core of the teaching of the One Vehicle.
Introduction to the Lotus Sutra