It seems this text has caused some confusion. Below is another quotation from Nichiren that I hope will make clear his meaning.

"You must never think that any of the eighty thousand sacred teachings of Shakyamuni Buddha’s lifetime or any of the Buddhas and bodhisattvas of the ten directions and three existences are outside yourself. Your practice of the Buddhist teachings will not relieve you of the sufferings of birth and death in the least unless you perceive the true nature of your life. If you seek enlightenment outside yourself, then your performing even ten thousand practices and ten thousand good deeds will be in vain. It is like the case of a poor man who spends night and day counting his neighbor’s wealth but gains not even half a coin. That is why the T’ien-t’ai school’s commentary states, 'Unless one perceives the nature of one’s life, one cannot eradicate one’s grave offenses.' This passage implies that, unless one perceives the nature of one’s life, one’s practice will become an endless, painful austerity. Therefore, such students of Buddhism are condemned as non-Buddhist. Great Concentration and Insight states that, although they study Buddhism, their views are no different from those of non-Buddhists.

"Whether you chant the Buddha’s name, recite the sutra, or merely offer flowers and incense, all your virtuous acts will implant benefits and roots of goodness in your life. With this conviction you should strive in faith."