The Synthesis of Yoga:

The sadhaka of the integral Yoga will make use of all these aids* according to his nature; but it is necessary that he should shun their limitations and cast from himself that exclusive tendency of egoistic mind which cries, “My God, my Incarnation, my Prophet, my Guru,” and opposes it to all other realisation in a sectarian or a fanatical spirit. All sectarianism, all fanaticism must be shunned. (p. 66)

* The knowledge of the truths, principles, powers and processes that govern the realisation; a patient and persistent action on the lines laid down by this knowledge; the direct suggestion, example and influence of the teacher; and the instrumentality of time.

If we are to attempt an integral Yoga, it will be as well to start with an idea of the Divine that is itself integral. There should be an aspiration in the heart wide enough for a realisation without any narrow limits. Not only should we avoid a sectarian religious outlook, but also all one-sided philosophical conceptions which try to shut up the Ineffable in a restricting mental formula. (p. 82)

The integral Yoga aims at a knowledge not merely of some fundamental principle, but a knowing, a gnosis which will apply itself to and cover all life and the world action, and in this search for knowledge we enter on the way and are accompanied for many miles upon it by the mind’s unregenerated activities before these are purified and transformed by a greater light: we carry with us a number of intellectual beliefs and ideas which are by no means all of them correct and perfect and a host of new ideas and suggestions meet us afterwards demanding our credence which it would be fatal to seize on and always cling to in the shape in which they come without regard to their possible error, limitation or imperfection. And indeed at one stage in the Yoga it becomes necessary to refuse to accept as definite and final any kind of intellectual idea or opinion whatever in its intellectual form and to hold it in a questioning suspension until it is given its right place and luminous shape of truth in a spiritual experience enlightened by supramental knowledge. (p. 772)

In the spiritual domain the essence is always one, but there is yet an infinite variety and, at any rate in the integral Yoga, the rigidity of a strict and precise mental rule is seldom applicable; for, even when they walk in the same direction, no two natures proceed on exactly the same lines, in the same series of steps or with quite identical stages of their progress. (p. 145)

Sri Aurobindo on Himself:

Nothing there [in the Arya] is written to support or to develop any kind of religious belief or dogma or to confirm or enunciate the credo of any old or new religion. (p. 90)

All fanaticism is false, because it is a contradiction of the very nature of God and of Truth. Truth cannot be shut up in a single book, Bible or Veda or Koran, or in a single religion. The Divine Being is eternal and universal and infinite and cannot be the sole property of the Mussulmans or of the Semitic religions only, those that happened to be in a line from the Bible and to have Jewish or Arabian prophets for their founders. Hindus and Confucians and Taoists and all others have as much right to enter into relation with God and find the Truth in their own way. All religions have some truth in them, but none has the whole truth; all are created in time and finally decline and perish. Mahomed himself never pretended that the Koran was the last message of God and there would be no other. God and Truth outlast these religions and manifest themselves anew in whatever way or form the Divine Wisdom chooses. You cannot shut up God in the limitations of your own narrow brain or dictate to the Divine Power and Consciousness how or where or through whom it shall manifest; you cannot put up your puny barriers against the divine Omnipotence. These again are simple truths which are now being recognised all over the world; only the childish in mind or those who vegetate in some formula of the past deny them. (p. 483)

Letters on Yoga:

Religious fanaticism is something psychologically low-born and ignorant — and usually in its action fierce, cruel and base. Religious ardour like that of the martyr who sacrifices himself only is a different thing. (p. 490)