[W]ithout the power of the Lotus Sūtra, it is impossible for any living being to attain Buddhahood, break through the six lower realms and be reborn in any of the Pure Lands of Buddhas throughout the universe. It is the same as a Japanese person who wishes to enter the Chinese Imperial Palace must first receive permission from the Japanese sovereign. You must rely on the power of the Lotus Sūtra in order to leave this Sahā World to enter a Pure Land. For example, if a woman, whether she be an ordinary woman or a daughter of the Imperial Regent, bears a king’s child, that child will someday become a king. On the other hand, if a daughter of a king bears a vassal’s child, that child can never become a king. Accordingly, all living beings including bodhisattvas, men of the Two Vehicles, human beings, heavenly beings and animals who will be reborn in Pure Lands throughout the universe do so as royal children of the Lotus Sūtra. It is because children of the Lotus Sūtra are all able to become Buddhas.

Shōjō Daijō Fumbetsu-shō, The Differences between Hinayāna and Mahāyāna Teachings, Writings of Nichiren Shōnin, Doctrine 2, Page 197