Link:--Lord Krsna, in the next verse, answers Arjuna's first question.
prajahati yada kamansarvanpartha manogatan
atmanyevatmana tustah sthitaprajnastadocyate
O Partha (Arjuna), when a man discards all his desires visiting the mind, and is self-satisfied in own self, he is said to be stable, in wisdom. 55
[According to the gospel of the Gita, a striver, can attain perfection, (God-realization), by any discipline (that of Disinterested Action or Devotion etc.) which he follows according to his interest and liking and his perfection is described by that means only. Example—A striver following the Discipline of Devotion worships God constantly, meditating on Him with exclusive devotion (12/6). Therefore, in the enlightened state, he becomes free from malice towards all beings (12/13). In the Discipline of Knowledge the striver perceives himself detached from these gunas (attributes) (modes) and is above them (14/19) and in the enlightened state, he sits like a witness firmly established in God, beyond all the gunas, having risen above them (14/22—25). Similarly, in Karmayoga it is the abandoning of all desires that is important.
Hence the enlightened soul abandons all desires. In this verse Lord Krsan dwells upon this point.]
Prajahati yada kamansarvanpartha manogatan:-It means that desire does not exist in the self, because the self is everlasting while desire is transient. Moreover it does not stay permanently in the mind but comes into it—'manogatan'. But the man by identifying himself with body, senses, mind and intellect, accepts the desire visiting the mind as resting in his own self.
'Jahati-Use of the prefix 'Pia' before the verb Prajahati, indicates that there is no trace of any desire left in him. A man can neither renounce his own self nor the things which are not his own, but he can renounce only the things which actually are not his own, but he has mistaken them as his own. Similarly, desires do not exist in one's own self, but one accepts them as existing in one's own self, so he has to cast them off.
The term 'kaman' (desires) also includes the term 'sarvan' (all), yet 'sarvan has been added to emphasize the fact that, every fragment of all the desires should be cast off.
Atmanyevatmana tustah:-After abandoning all the desire completely, a man is satisfied in himself and with himself i.e., he is spontaneously contented in his own self.
Contentment is of two kinds-one is said to be a virtue as it relates to inner sense. It is there as a result of no desire in the inner sense. But the other kind is the self itself. As the self never has any trace of discontentment so it is called contentment incarnate the Self itself). The latter contentment is eternal. It knows no change. It is spontaneous. It is not the result of any practice or thought. The intellect of such a contented men always remains steadfast automatically.
Sthitaprajnastadocyate:-Actually a man is always steady in wisdom, but when he accepts his desires, because of unsteady mind, he does not realize his stableness in wisdom. When he abandons his desires viz., accepts the non-existence of desires, he realizes his stability in wisdom.