The traditional religious conception views money-making and God-seeking as incompatible pursuits. But in this letter to a disciple Sri Aurobindo explains that in an integral spiritual perspective, spiritual growth does not depend so much on the outer act but on the inner attitude:

I may say, however, that I do not regard business as something evil or tainted, any more than it is so regarded in ancient spiritual India. If I did, I would not be able to receive money from X or from those of our disciples who in Bombay trade with East Africa; nor could we then encourage them to go on with their work but would have to tell them to throw it up and attend to their spiritual progress alone. How are we to reconcile X’s seeking after spiritual light and his mill? Ought I not to tell him to leave his mill to itself and to the devil and go into some Ashram to meditate? Even if I myself had had the command to do business as I had the command to do politics I would have done it without the least spiritual or moral compunction. All depends on the spirit in which a thing is done, the principles on which it is built and the use to which it is turned. I have done politics and the most violent kind of revolutionary politics, ghoram karma, and I have supported war and sent men to it, even though politics is not always or often a very clean occupation nor can war be called a spiritual line of action. But Krishna calls upon Arjuna to carry on war of the most terrible kind and by his example encourage men to do every kind of human work, sarvakarmani. Do you contend that Krishna was an unspiritual man and that his advice to Arjuna was mistaken or wrong in principle? Krishna goes further and declares that a man by doing in the right way and in the right spirit the work dictated to him by his fundamental nature, temperament and capacity and according to his and its dharma can move towards the Divine. He validates the function and dharma of the Vaishya as well as of the Brahmin and Kshatriya. It is in his view quite possible for a man to do business and make money and earn profits and yet be a spiritual man, practise yoga, have an inner life. The Gita is constantly justifying works as a means of spiritual salvation and enjoining a Yoga of Works as well as of Bhakti and Knowledge. Krishna, however, superimposes a higher law also that work must be done without desire, without attachment to any fruit or reward, without any egoistic attitude or motive, as an offering or sacrifice to the Divine. This is the traditional Indian attitude towards these things, that all work can be done if it is done according to the dharma and, if it is rightly done, it does not prevent the approach to the Divine or the access to spiritual knowledge and the spiritual life.
There is, of course, also the ascetic idea which is necessary for many and has its place in the spiritual order. I would myself say that no man can be spiritually complete if he cannot live ascetically or follow a life as bare as the barest anchorite’s. Obviously, greed for wealth and money-making has to be absent from his nature as much as greed for food or any other greed and all attachment to these things must be renounced from his consciousness. But I do not regard the ascetic way of living as indispensable to spiritual perfection or as identical with it. There is the way of spiritual self-mastery and the way of spiritual self-giving and surrender to the Divine, abandoning ego and desire even in the midst of action or of any kind of work or all kinds of work demanded from us by the Divine. If it were not so, there would not have been great spiritual men like Janaka or Vidura in India and even there would have been no Krishna or else Krishna would have been not the Lord of Brindavan and Mathura and Dwarka or a prince and warrior or the charioteer of Kurukshetra, but only one more great anchorite. The Indian scriptures and Indian tradition, in the Mahabharata and elsewhere, make room both for the spirituality of the renunciation of life and for the spiritual life of action. One cannot say that one only is the Indian tradition and that the acceptance of life and works of all kinds, sarvakarmani, is un-Indian, European or western and unspiritual.
[SABCL, 23:67576]
It is said, “One cannot make a heap without making a hole”, one cannot enrich oneself without impoverishing someone else. Is this true?
This is not correct. If one produces something, instead of an impoverishment it is an enrichment; simply one puts into circulation in the world something else having a value equivalent to that of money. But to say that one cannot make a heap without making a hole is all right for those who speculate, who do business on the Stock Exchange or in finance—there it is true. It is impossible to have a financial success in affairs of pure speculation without its being detrimental to another. But it is limited to this. Otherwise a producer does not make a hole if he heaps up money in exchange for what he produces. Surely there is the question of the value of the production, but if the production is truly an acquisition for the general human wealth, it does not make a hole, it increases this wealth. And in another way, not only in the material field, the same thing holds for art, for literature or science, for any production at all.
When I was doing business (exportimport), I always had the feeling of robbing my neighbour.
This is living at the expense of others, because one multiplies the middlemen. Naturally, it is perhaps convenient, practical, but from the general point of view, and above all in the way it is practised, it is living at the expense of the producer and the consumers. One becomes an agent, not at all with the idea of rendering service (because there is not one in a million who has this idea), but because it is an easy way of earning money without making any effort. But of course, among the ways of making money without any effort, there are others much worse than that! They are countless.
[CWM2, 4:37576]
When one is compelled to earn his living, should one just conform to the common code of honesty or should one be still more strict?
This depends upon the attitude your friend has taken in life. If he wants to be a sadhak, it is indispensable that rules of ordinary morality do not have any value for him. Now, if he is an ordinary man living the ordinary life, it is a purely practical question, isn’t it? He must conform to the laws of the country in which he lives to avoid all trouble! But all these things which in ordinary life have a very relative value and can be looked upon with a certain indulgence, change totally the minute one decides to do yoga and enter the divine life. Then, all values change completely; what is honest in ordinary life, is no longer at all honest for you. Besides, there is such a reversal of values that one can no longer use the same ordinary language. If one wants to consecrate oneself to the divine life, one must do it truly, that is, give oneself entirely, no longer do anything for one’s own interest, depend exclusively upon the divine Power to which one abandons oneself. Everything changes completely, doesn’t it?—everything, everything, it is a reversal. What I have just read from this book applies solely to those who want to do yoga; for others it has no meaning, it is a language which makes no sense, but for those who want to do yoga it is imperative. It is always the same thing in all that we have recently read: one must be careful not to have one foot on one side and the other foot on the other, not to stand in two different boats each following its own course. This is what Sri Aurobindo said: one must not lead a “double life”. One must give up one thing or the other—one can’t follow both.
This does not mean, however, that one is obliged to get out of the conditions of one’s life: it is the inner attitude which must be totally changed. One may do what one is in the habit of doing, but do it with quite a different attitude. I don’t say it is necessary to give up everything in life and go away into solitude, to an ashram necessarily, to do yoga. Now, it is true that if one does yoga in the world and in worldly circumstances, it is more difficult, but it is also more complete. Because, every minute one must face problems which do not present themselves to someone who has left everything and gone into solitude; for such a one these problems are reduced to a minimum—while in life one meets all sorts of difficulties, beginning with the incomprehension of those around you with whom you have to deal; one must be ready for that, be armed with patience, and a great indifference. But in yoga one should no longer care for what people think or say; it is an absolutely indispensable starting-point. You must be absolutely immune to what the world may say or think of you and to the way it treats you. People’s understanding must be something quite immaterial to you and should not even slightly touch you. That is why it is generally much more difficult to remain in one’s usual surroundings and do yoga than to leave everything and go into solitude; it is much more difficult, but we are not here to do easy things—easy things we leave to those who do not think of transformation.
[CWM2, 4:37678]