Among those who have attained this higher life, who feel its power and sense its peace, there are some who wish that others shall attain it too. We say some for the very powerful reason that not all are able to find it in their hearts to return to this bleak earth of ours, with its sickness and darkness, its sins and sufferings, its evil and ignorance, when there stretches invitingly before them the portals of a diviner world, with its sublime harmony and beauty, its burden-free peace and goodness. This is why Krishna is reported in the Bhagavad Gita as declaring that the greatest sacrifice man can offer is that of wisdom, which means simply that the enlightened man should give himself and use his wisdom for the benefit of others. This is also why Buddha asserted that the greatest charity is to give the truth to mankind. Therefore, the noblest sages give themselves secretly and concentratively to a few or openly and widely to the many to enlighten, guide, and inspire them. They know that this twofold way is the one in which to help mankind, that public work is not enough, that those who wish to do not only the most widespread good in the time open to them but also the most enduring good, must work deeply and secretly amongst a few who have dedicated themselves to immediate or eventual service in their own turn. Thus, compassion is rendered more effective through being guided by intelligence. To the few in the inner circle, the sage transmits his best thought, his hidden knowledge, his special grace, his most mystical power. How grand is the service such a sage can render all those who accept the light of his knowledge! Then indeed is he, in Shakespeare's phrase, "The star to every wandering barque."
-- Notebooks Category 25: World-Mind in Individual Mind > Chapter 5: The Sage's Service > # 4