य एनं वेत्ति हन्तारं यश्चैनं मन्यते हतम्।उभौ तौ न विजानीतो नायं हन्ति न हन्यते॥
ya enaṃ vetti hantāraṃ yaś cainaṃ manyate hatamubhau tau na vijānīto nāyaṃ hanti na hanyate
Word by word
The verse says
Whoever thinks this kills, and whoever thinks this is killed, have both misunderstood. It does not kill. It is not killed.
In plain words
Both sides of the transaction are wrong.
The one who thinks he is the killer. The one who thinks he is being killed. Neither has understood what is actually happening.
Notice that Krishna does not only relieve Arjuna of being the slayer. He removes the other half too.
Where you've felt this · in relationships
Two people in a long argument each convinced they are doing something decisive to the other. Years later neither can remember what was said, and both were changed by things neither of them chose.
Going deeper
This verse is almost word for word from the Katha Upanishad, and the Gita's first listeners would have recognised it. Krishna is quoting, and quoting deliberately.
That is worth knowing. The Gita is not inventing this from nothing; it is placing an old teaching into a situation where it costs something to believe.
The logic is tight. Killing requires an agent who acts and a patient who is acted upon. If what is essential in a person is neither produced nor destroyed, then the event we call killing happens entirely among the things that were changing anyway.
But hold onto what this does not say. It does not say the act is morally weightless. The Gita has a great deal to say elsewhere about how and why an act is done, and Chapter 16 is unsparing about cruelty. What is being denied is a metaphysical claim, not an ethical one.
This distinction is easy to lose, and losing it produces the worst readings of the book. You cannot annihilate a person is not the same sentence as it does not matter what you do to them.