The heart of the Buddha's lifetime of teachings is the Lotus Sutra, and the heart of the practice of the Lotus Sutra is found in the "Never Disparaging" chapter.

Buddhism Day by Day

Wisdom for Modern Life by Daisaku Ikeda
Thursday, July 11, 2013:

The heart of the Buddha's lifetime of teachings is the Lotus Sutra, and the heart of the practice of the Lotus Sutra is found in the "Never Disparaging" chapter. What does Bodhisattva Never Disparaging's profound respect for people signify? The purpose of the appearance in this world of Shakyamuni Buddha, the lord of teachings, lies in his behavior as a human being. -Nichiren