The faith in and the practice of reverential worship into which he was initiated by religion must not be dropped. It is required by philosophy also. Only, he is to correct, purify, and refine it. He is to worship the divine presence in his heart, not some distant remote being, and he is to do so more by an act of concentrated thought and unwavering feeling than by resort to external indirect and physical methods. With the philosopher, as with the devotee, the habit of prayer is a daily one. But whereas he prays with light and heat, the other prays with heat alone. The heart finds in such worship a means of pouring out its deepest feelings of devotion, reverence, humility, and communion before its divine source. Thus we see that philosophy does not annul religious worship, but purifies and preserves what is best in it. It does annul the superstitions, exploitations, and futilities connected with conventional religious worship. In the end philosophy brings the seeker back to religion but not to a religion: to the reverence for a supreme power which he had discarded when he discarded the superstitions which had entwined themselves around it. Philosophy is naturally religious and inevitably mystical. Hence it keeps intact and does not break to pieces that which it receives from religion and yoga. It will, of course, receive only their sound fruits, not their bad ones. Philosophic endeavour does not, for instance, disdain religious worship and humble prayer merely because its higher elements transcend them. They are indeed part of such endeavour. But they are not, as with religionists, the whole of it. The mystic must not give up being religious merely because he has become a mystic. In the same way, the philosopher must not give up being both mystical and religious merely because he has become a philosopher. It is vitally important to know this. Philosophy does not supersede religion but keeps it and enlarges it.
-- Notebooks Category 20: What Is Philosophy? > Chapter 1: Toward Defining Philosophy > # 454
-- Perspectives > Chapter 20: What Is Philosophy? > # 28