इति ते ज्ञानमाख्यातं गुह्याद्गुह्यतरं मया।विमृश्यैतदशेषेण यथेच्छसि तथा कुरु॥
iti te jñānam ākhyātaṃ guhyād guhyataraṃ mayāvimṛśyaitad aśeṣeṇa yathecchasi tathā kuru
Word by word
The verse says
So I have explained to you the knowledge that is more secret than any secret. Think it over completely, and then do as you choose.
In plain words
This is the hinge of the entire book, and it is seven words long.
Yathecchasi tathā kuru - do as you choose.
After seven hundred verses. After the argument, the vision, the warnings, the promise. The decision is handed back, intact, to the man who has to make it.
Where you've felt this · in parenting
A father spends an hour laying out, as fairly as he can, why he thinks his daughter should not take the job in another country. He makes every point he has. Then he says: you have heard all of it, and it is your life, and whatever you decide I am with you. She takes the job. He meant what he said.
Going deeper
Handing back the decision after arguing that hard for one side is the most significant thing Krishna does, and it defines what kind of book this is.
Everything was available to him. He is the teacher, the friend, the charioteer, and twelve chapters ago he showed Arjuna a form that terrified him into silence. Compulsion was never off the table, and he had already said in 18.59 that Arjuna's refusal would not hold.
And then: think it over completely, and do as you choose. The word for thinking it over means to turn it over fully, which assumes a person capable of weighing it. The choice is not given back as a formality. It is given back with everything required to make it.
This is also the answer to the machine verse two lines earlier, as far as any answer is given. Whatever it means to be turned by something seated in your own heart, it evidently does not mean this sentence is empty. A reader is being told that the most anyone can do for you, including God, is tell you the truth as completely as possible and then leave it with you.