sarvadharmaanparitajya maamekam sharanam vraja |
aham tvaa sarvapaapebhyo mokshayishyaami maa shuchaha || 66 ||

Abandoning all duties, take refuge in me alone. I shall liberate you from all sins. Do not grieve.
sarvadharmaan : all duties
paritajya : abandoning
maam : me
ekam : alone
sharanam : refuge
vraja : take
aham : I
tvaa : you
sarvapaapebhyaha : from all sins
mokshayishyaami : shall liberate
maa : do not
shuchaha : grieve
When someone joins a large corporation for the first time, they take several months to understand the lay of the land. This is because their boss may tell them to do one thing, but their boss’s boss may tell them to do something else. The sales team may offer suggestions that are completely opposed to the marketing team’s view. The new employee will be totally confused till they figure out a sort of compromise. But, if by chance, the new employee meets the CEO of the company and gets their opinion, they will have a clear and unambiguous direction.
It is said that this shloka, containing the sum and substance of the entire Gita, is the one “take home message” for any student who feels bewildered or overwhelmed with the teaching. There are four parts to the shloka. The first part instructs the seeker to abandon all of their duties. Let us look at this deeper meaning since we should not take it literally. This means that Shri Krishna wants the seeker to stop analyzing which actions they should stop performing, which actions should they continue pursuing and which new actions should they take up. They should simply stop worrying about all these questions.
So then, what should the seeker do? The second part of the shloka gives the answer – take refuge in Ishvara alone. All our thoughts, words, actions, feelings, everything should be dedicated towards Ishvara. By doing so, we will automatically arrive at the answers to our questions regarding what to do and what not to do. If we eat our food by first offering it to Ishvara, we will automatically stop eating food that is not appropriate. If we offer all of our actions to Ishvara, we will not perform any illegal or unethical actions. Everything will automatically fall into place.
What is the result of taking refuge in Ishvara? The third part of the shloka assures the seeker that they will be liberated from all of their paapa, their sins. Sins in this context refers to the bondage of actions caused by our ego. If we perform all actions in service to Ishvara, and accept any success or failure as a gift from Ishvara, we will never harbour any worry or anxiety about the past or future. We will simple continue to fill our time in relentless service to Ishvara. Ultimately, we will reach a stage where our mind is purified of all selfishness, leading to the fourth part of the shloka, complete freedom from sorrow.
Shri Krishna ends this shloka with the words “do not grieve”. It is said that the core teaching of the Gita is complete, since the teaching was begun with a view to eliminate the cause of Arjuna’s sorrow, which is his ignorance of his true nature as the self.