evam buddheh param buddhvaa sanstabhyaatmaanamaatmanaa |
jahi shatrum mahaabaaho kaamaroopam duraasadam || 43 ||

In this way, having known the eternal essence to be superior than the intellect, and having strengthened oneself by oneself, O mighty-armed, slay the insurmountable enemy in the form of desire.

evam : in this way
buddheh : with intellect
param : superior (the eternal essence)
buddhvaa : having known
sanstabhyaha : strengthened
aatmaanam : oneself
aatmanaa : by oneself
jahi : slay
shatrum : enemy
mahaabaaho : O mighty-armed
kaamaroopam : in the form of desire
duraasadam : insurmountable

The prior shloka and this shloka comprise the concluding shlokas of the third chapter. In these 2 shlokas, Shri Krishna gives Arjuna the seed of an entire lifetime’s worth of spiritual practice. But this technique needs further elaboration, which will be provided in the forthcoming chapters of the Gita. Karmayoga is just the preparatory stage. The real journey of spiritual practice or saadhanaa commences only when we learn to control and channel our vaasanaas through karmayoga, which culminates in the practice of meditation.

One of the major points made in this shloka is that we have tackle our problems from the standpoint of the eternal essence, not from the standpoint of our prakriti, which is not our real identity. We have been conditioned to identify with our prakriti since our birth, which is what makes it difficult. Therefore, to the extent possible, we should always try to identify with the eternal essence.

For instance, we come across a thought that says “I can smoke one cigarette today, it will cause me no harm”, we have to be alert and ask ourselves, who is this I that has generated this thought? If we are truly identified with the eternal essence, we will recognize that our prakriti – our inbuilt tendency – is saying it. This is not easy to do. Typically, when such a thought arises, it “short-circuits” our intellect and turns into action immediately. That is why Shri Krishna urges us to start on the path of karmayoga so that we slowly lose attachment with material objects first, then with our body/mind/intellect.

This inner conflict between our lower nature and our higher nature is the central theme of the Gita. Therefore, Shri Krishna concludes the chapter on karmayoga with a profound message: strengthen oneself by oneself. It means that by practicing karmayoga, we strengthen our higher nature, and that enables us to control our lower nature.

om tatsatiti shreematbhagavatgitasupanishadsu brahmavidyaayaam yogashaastre shreekrishnaarjunsamvade karmayogo naama tritiyodhyaayaha || 3 ||