Arhat is both the way and the waygoer; and while the term is close philosophically to anagamin, the distinction between the two lies in their mystical connotations rather than in their etymological definitions. Arhat has a wider significance inasmuch as it applies to those noblest of the Buddha's disciples who were "worthy" of receiving, because comprehending, the Tathagata's heart doctrine, the more esoteric and mystical portions of his message.
As early as one hundred years after the Buddha died and had entered his parinirvana, differences in the doctrines and discipline of the Order become manifest. In the course of the centuries two basic trends developed into what has become popular to call the Hinayana (the lesser vehicle or path) or Theravada (doctrine of the elders), and Mahayana (the greater vehicle or path). The Theravada emphasized the fourfold path leading to nirvana, total liberation of the arhat from material concerns. The Mahayana held the bodhisattvayana as the ideal, the way of compassion for all sentient beings, culminating in renunciation of nirvana in order to return and inspire others "to awake and follow the dhamma." It is this fundamental difference in goal that characterizes the Old Wisdom School (arhatship) from the New Wisdom School (bodhsattvahood).
See also DHYANI-BUDDHA ; Pratyeka Buddhas
