''When at the start of the great war of Kurukshetra the exchange of missiles had begun, pravṛtte śastra-sampāte, it was at that moment that the Lord revealed the Gita. To many this has occasioned surprise and annoyance; they say it must have been due to the author's carelessness or faulty intelligence. But in actual fact, Sri Krishna revealed the knowledge contained in the Gita, at that particular moment and in that situation to a person in that frame of mind, with full knowledge of the time, place and circumstance.

The time was at the commencement of the war. Those who have not developed or put to a test their heroic qualities or strength in a mighty flood of action can never be fit to receive the knowledge given in the Gita. 

Moreover those who have embarked on a great and difficult endeavour, an endeavour which automatically gives rise to many obstacles and obstructions, many enmities, fears of many setbacks, when in the course of that great endeavour there is acquired a divine strength, to them at that moment in order to take the endeavour to its final conclusion, for the successful carrying out of the divine's work is this knowledge revealed. 

The Gita lays down in the Yoga of works the foundations of the path to God. It is through works done with faith and devotion that knowledge is born. Therefore the traveller on the path indicated by the Gita does not leave the path and have the vision of God in a remote and quiet hermitage or hill or in a secluded spot; that heavenly Light illumines the world for him, that sweet and powerful Word comes within his hearing, all of a sudden in midway, amidst the noise and bustle of works.

The place was a battlefield, between two armies where missiles were flying. To those who travel on this path, take the lead in works of this nature, often the realisation, yoga-siddhi, comes and the supreme knowledge dawns, all of a sudden at a critical and momentous hour which determines the march of destiny in this direction or that, depending on the nature of their acts. That knowledge is no bar to action, it is intimately connected with action. It is no doubt true that knowledge also dawns in meditation, in loneliness, when one turns back on one's self; that is why the sages love to be alone. But the traveller on the path of the Gita's Yoga can so divide his instruments of mind, life and body that he experiences loneliness in the midst of a crowd, peace amidst noise, supreme repose while engaged in a whirl of activities. He does not regulate the inner being by outward circumstances, he controls the outer by the inner state. The ordinary Yogin is afraid of life, he escapes from it and takes to Yoga in the shelter and protection of an Ashram. Life itself is the Ashram for the Karmayogin. 

The ordinary Yogin desires an outward peace and silence, a disturbance of the peace impedes his inner askesis. The Karmayogin enjoys a vast peace and silence within; this state becomes deeper in the midst of external noise; any external disturbance does not harm that inner askesis, it remains undisturbed. People say, how was the Sri Krishna-Arjuna dialogue possible in the middle of armies going in for battle? The answer is, it was possible through the power of Yoga.

Through that power of Yoga, amidst the din of battle, at one particular spot, with Sri Krishna and Arjuna peace reigned within and without; the noise of war could not affect these two. In this is implied another spiritual teaching applicable to works. 

Those who practise the Gita's yoga are the most capable workers and yet remain unattached to their work. Right in the midst of their work they may hear the inner call of the Self, desist from the work and plunge themselves in yoga and do the inner askesis. They know that the work is God's, the fruit is His, we are instruments; hence they have no anxiety about the fruit of their work. They also know that the inner call comes for facilitating the yoga of works, for an improvement in the working, for the increase of knowledge and power. Therefore they do not fear to desist from their work; they know that in the spiritual effort there can never be an unnecessary waste of time.''

Sri Aurobindo - An Introduction to The Gita [from His writings in Bengali and Sanskrit, translation by others]