Nichiren Daishonin's gosho 'The Gift of Rice' explains the sincerity of offering while emphasizing the value of life.
Man has two kinds of treasure, he saya, - clothing and food. Man depends on clothing and food to stay alive. But life itself is the most precious treasure. Even the treasures of the entire universe cannot equal the value of a single human life.
The boy Snow Mountains (Sessen Doji) offered his body to a demon to receive a teaching composed of eight characters (see the writing "14 Slanders"). Boddhisttva Yakuo, having no oil, burned his elbow as an offering to the Lotus Sutra. Prince Shotoku peeled off the skin of his hand on which to copy the Lotus Sutra and Emperor Tenji burned his third finger as an offering to Shakymuni Buddha. Such austere practices are for saints and sages but not for ordinary people.
The word "nam" derives from sanskrit and means to devote one's life. Ultimately it means to offer our lives to the Buddha. Whether man has wealth or not, life is still the most important treasure. Accordingly, saints and sages of ancient times offered their lives to the Buddha and were themselves able to attain Buddhahood.
Even common mortals can attain Buddhahood if they possess earnest faith. Earnest faith is the will to understand and live up to the spirit, not the words, of the sutras. It means that offering one's only coat to the Lotus Sutra or, in a time of famine, offering one's food on which life depends is equivalent to the acts of Sessen Doji and other sages. Therefore, saints consecrated themselves by offering their own bodies, but common mortals can do so by the sincerity with which they give.
The true path of life lies in the affairs of this world. Pre Lotus Sutra teachings expounded the duality of life - that they relate secular matters in terms of Buddhism. In contrast, the Lotus Sutra teaches that secular matters are Buddhism. Based on thsis oneness of life and environment, rice is not merely rice, but life itself.