Someone may wonder: “Among the sūtras transmitted to China and Japan, not one may be superior to the Lotus Sūtra. But there are numerous sūtras in India, in the Dragon Palace, in the heavens of the Four Heavenly Kings, in the sun and moon and in Trāyastriṃsá Heaven (abode of Indra at the top of Mt. Sumeru) and Tuṣita Heaven (abode of Bodhisattva Maitreya). It may be possible to find a sūtra among them which is superior to the Lotus Sūtra.”

In response, I would say that we can judge in general by observing one instance. We can see what is going on in the world without going out of the door. Ignorant people who look at the sky only in the south without looking at the sky in other directions may think that there is a sun in each direction. Seeing smoke hanging over a mountain, they may say that it is not a fire, because they do not see any flames. Those who think in such a way, you should know, are icchantika. They are nothing but blind fools!

Hōon-jō, Essay on Gratitude, Writings of Nichiren Shōnin, Doctrine 3, Pages 5.