tasmaadajnyaanasambhootam hritstham jnyaanaasinaatmanaha |
chhittavainam sanshayam yogamaatishthottishtha bhaarata || 42 ||

Therefore, with the sword of knowledge, tear your doubts that are born of ignorance and reside in your heart; establish yourself in this path of yoga, and arise, O Arjuna.

tasmaat : therefore
ajnyaana : ignorance
sambhootam : born of
hritstham : reside in the heart
jnyaana : knowledge
asina : sword of
aatmanaha : your
chhittavaa : tear
enam : this
sanshayam : doubts
yogam : yoga
aatishtha : establish yourself (in this path)
uttishtha : arise
bhaarata : O Bhaarata

In this concluding verse of the fourth chapter, Shri Krishna urges Arjuna to cast away all his doubts and get back to fighting the Kurukshetra war. In other words, he asks the students of the Gita to put the teaching of the fourth chapter into practice, and to act in this world.

Shri Krishna reiterates the location of our accumulated ignorance. He uses the word “hritstham” which literally means heart, but actually refers to the four-fold antaha-karana comprising the mind, intellect, memory and ego.

This shloka also provides a concise summary of the fourth chapter. Ignorance in the form of individuality, selfishness and finitude, is our natural condition. This ignorance causes us to question our relationship with the world, just like Arjuna got confused in regards to his duty as a warrior. Having gained knowledge, in the form of universality, selflessness and infinitude, we know exactly how to transact with the world. All our doubts are destroyed. We begin to act in a spirit of yajnya, where we see the same eternal essence in the actor, the action and the result. Ultimately, like the shloka says, we arise not just physically, but also spiritually, into a new level of consciousness.

om tatsatiti shrimadbhagavadgitasu upanishadsu brahmavidyayaam yogashastre shrikrishnaarjunasamvade
jnyaanakarmasanyaasayogonaamo chaturthodhyaahaha || 4 ||