It is the tendency of the human mind to try to apply distinctions universally. Therefore, we tend to want to classify people according to whether they are of the deva or the asura nature. Sri Aurobindo cautions us to recognise, however, that for most people, these distinctions are not at all relevant. “The distinction between the Deva and the Asura is not comprehensive of all humanity, not rigidly applicable to all its individuals, neither is it sharp and definite in all stages of the moral or spiritual history of the race or in all phases of the individual evolution. The tamasic man who makes so large a part of the whole, falls into neither category as it is here described, though he may have both elements in him in a low degree and for the most part serves tepidly the lower qualities. The normal man is ordinarily a mixture; but one or the other tendency is more pronounced, tends to make him predominantly rajaso-tamasic or sattwo-rajasic and can be said to be preparing him for either culmination, for the divine clarity or the titanic turbulence.”
The distinction can be applied to the individual of highly developed capacity, and depends on the turning of the focus and the action of the nature either toward the Divine or toward the fulfillment and aggrandisement of the ego. “The Deva nature is distinguished by an acme of the sattwic habits and qualities; self-control, sacrifice, the religious habit, cleanness and purity, candour and straightforwardness, truth, calm and self-denial, compassion to all beings, modesty, gentleness, forgivingness, patience, steadfastness, a deep sweet and serious freedom from all restlessness, levity and inconstancy are its native attributes.” This is not to say that the sattwic soul is weak. “…it has energy and soul-force, strong resolution, the fearlessness of the soul that lives in the right and according to the truth as well as its harmlessness…. The whole being, the whole temperament is integrally pure; there is a seeking for knowledge and a calm and fixed abiding in knowledge. This is the wealth, the plenitude of the man born into the Deva nature.”
Arjuna actually represents the type of the Deva nature at the acme of human development. Even his paralysis at the inception of the battle of Kurukshetra has a sense of wideness, compassion and harmlessness in it. Sri Krishna makes it clear to Arjuna that fighting this battle for higher principles of right is not the same as the action of an Asuric man bent on inflicting suffering and pain in order to achieve egoistic domination over others; and therefore, Arjuna need not worry: he is of the Deva nature.
Sri Aurobindo, Essays on the Gita, Second Series, Part II, Chapter 17, Deva and Asura, pp. 455-456