Link:-The Lord answers the question, in the next verse.
kama esa krodha esa rajogunasamudbhavah
mahasano mahapapma viddhyenamiha vairinam
The Blessed Lord said:
An Important Fact Pertaining to Desire
It is desire and it is anger, born of the mode of passion (rajas), most greedy and most sinful. Know this to be the enemy concerned. 37
'Rajogunasamudbhavah'—The Lord, in the seventh verse of the fourteenth chapter, declares, "The mode of passion springs from desire and attachment", while here, He declares that desire is born of a mode of passion. It means, that desire is born of the mode of passion, while desire enhances passion (attachment). A person believes that worldly objects provide him pleasure, so he has a desire to acquire them in order to enjoy pleasure. This desire, gives birth to attachment. So long as this process continues, he cannot get rid of sinful acts.
Kama esa krodha esa:-A man, has a desire for sensual pleasure and prosperity. Sometimes, sins are committed under the sway of desire, while other times, these are committed, under the sway of anger. Through desire and anger, different types of sins are committed. Therefore, these two terms have been used. This desire is the root of all sin. When it is not satisfied, it gives birth to anger. The singular number, has been used for desire and anger in order to explain that only desire is the root of sins.
When a desire is satisfied, it gives birth to greed; but if it is not satisfied, it gives birth to anger. If the person, who is a stumbling block to the satisfaction of our desire, is more powerful than we, fear is born instead of anger. Therefore, in the Gita, besides desire and wrath, fear has also been mentioned as `delivered from desire, fear and anger' (4/10) and 'free from desire, fear and anger' (5/28).
Whatever we may desire, does not happen, and whatever we do not desire, happens—this is suffering. Desire is the root of all sins and sufferings. A man with a desire cannot get happiness, even in a dream (Hansa 7/90/1). If desire is renounced, there is no question of any suffering. Craving for perishable objects, is called desire, while the need for God-realization, which may appear to be like desire, is not really desire. The reason is, that desire is never satisfied, but it is strengthened by sense enjoyments, while the need of God-realization, is fulfilled having realized God. A man has desire for something, which is different from him (the self), while God is one with the self. Similarly, the need of rendering selfless service (the Discipline of Action), Self-realization (the Discipline of Knowledge) and devotion to God (the Discipline of Devotion) are not desires. In fact, the need of the self (soul) is to realize God but he (the self) has a desire to acquire the perishable objects etc., because his discrimination is veiled.
A doubt may arise here as to how the worldly affairs will go on, without desire. The clarification is, that worldly affairs relate with actions and commodities; rather than with desires. Actions are performed outwardly and so their fruit in the form of objects and circumstances etc., is also external, while desire is internal.