B.G 2.19

य एनं वेत्ति हन्तारं यश्चैनं मन्यते हतम् । उभौ तौ न विजानीतो नायं हन्ति न हन्यते॥१९ ॥

ya enaṃ vetti hantāraṃ yaścainaṃ manyate hatam । ubhau tau na vijānīto nāyaṃ hanti na hanyate॥19॥

[यः (yaḥ) - who; एनम् (enam) - this; वेत्ति (vetti) - knows; हन्तारम् (hantāram) - killer; यः (yaḥ) - who; च (ca) - and; एनम् (enam) - this; मन्यते (manyate) - thinks; हतम् (hatam) - killed; उभौ (ubhau) - both; तौ (tau) - they; न (na) - not; विजानीतः (vijānītaḥ) - know; न (na) - not; अयम् (ayam) - this; हन्ति (hanti) - kills; न (na) - not; हन्यते (hanyate) - is killed;]

(The one who believes the soul to be a slayer and the one who thinks it can be slain are both ignorant. The soul kills not, nor is it killed.)

He who thinks a person to be a killer, and he who thinks another person as killed - both of them are ignorant. He does not kill nor does the other get killed.

Gīta Bhāshya 2.19

The Lord is the real doer.

व्यवहारस्तु भ्रान्त इत्याह य एनम् इ ति। कुतः उक्तहेतुभ्यो नायं हन्ति न हन्यते। नहि प्रतिबिम्बस्य क्रिया। स हि बिम्बक्रिययैव क्रियावान्। 'ध्यायतीव' (बृ.उ.६.३.७) इति श्रुतेश्च ॥१९॥

vyavahārastu bhrānta ityāha ya enam iti। kutaḥ uktahetubhyo nāyaṃ hanti na hanyate। nahi pratibimbasya kriyā। sa hi bimbakriyayāiva kriyāvān। 'dhyāyatīva' (bṛ.u.6.3.7) iti śruteśca ॥19॥

[व्यवहारः (vyavahāraḥ) - transaction; तु (tu) - but; भ्रान्तः (bhrāntaḥ) - deluded; इति (iti) - thus; आह (āha) - says; यः (yaḥ) - who; एनम् (enam) - this; इति (iti) - thus; कुतः (kutaḥ) - why; उक्तहेतुभ्यः (uktahetubhyaḥ) - from the stated reasons; न (na) - not; अयम् (ayam) - this; हन्ति (hanti) - kills; न (na) - not; हन्यते (hanyate) - is killed; नहि (nahi) - not; प्रतिबिम्बस्य (pratibimbasya) - of the reflection; क्रिया (kriyā) - action; सः (saḥ) - he; हि (hi) - indeed; बिम्बक्रियया (bimbakriyayā) - by the action of the original; एव (eva) - only; क्रियावान् (kriyāvān) - active; ध्यायति (dhyāyati) - meditates; इव (iva) - as if; इति (iti) - thus; श्रुतेः (śruteḥ) - from the scripture; च (ca) - and;]

(The worldly dealings are indeed deluded, says he who perceives this. Why? Because, as stated, this neither kills nor is killed. The reflection has no action of its own; it acts only through the action of the original. The scripture also states 'as if meditates' (Bṛ.U.6.3.7).)

Only those who are disillusioned by material transactions argue - "I am doing". Why? The reason is stated, “neither kills nor is killed”. Reflected images can't initiate action. Only when the original object moves, he moves. Hence, there are Vedic statements such as “dyayativa” i.e. “Lord makes Jiva worship”.

Gīta Tātparya 2.19

Jīva is not an independent agent. The above verse is not to show a person does not get killed, as it contradicts with later verse 11.34, which states - “kill those whom I have already killed”.

यः एनं जीवं वेत्ति हन्तारं स्वातन्त्र्येण। अन्यथा 'मया हतांस्त्वं जहि' इत्यादिविरोधः । चेतनं प्रति य एनमिति परमात्मनोपि समम् ॥१९॥

yaḥ enaṃ jīvaṃ vetti hantāraṃ svātantryeṇa। anyathā 'mayā hatāṃstvaṃ jahi' ityādivirodhaḥ । cetanaṃ prati ya enamiti paramātmanopi samam ॥19॥

[यः (yaḥ) - who; एनम् (enam) - this; जीवम् (jīvam) - living being; वेत्ति (vetti) - knows; हन्तारम् (hantāram) - killer; स्वातन्त्र्येण (svātantryeṇa) - independently; अन्यथा (anyathā) - otherwise; मया (mayā) - by me; हतान् (hatān) - killed; त्वम् (tvam) - you; जहि (jahi) - conquer; इत्यादि (ityādi) - etc.; विरोधः (virodhaḥ) - contradiction; चेतनम् (cetanam) - consciousness; प्रति (prati) - towards; यः (yaḥ) - who; एनम् (enam) - this; इति (iti) - thus; परमात्मनोपि (paramātmanopi) - even the Supreme Soul; समम् (samam) - equally;]

(The one who perceives this living being as an independent killer contradicts the statement 'you conquer those killed by me'. This applies equally to consciousness and even to the Supreme Soul.)

One who thinks the person as a killer is ignorant, as he is attributing independent agency to a killer. Interpreting the verse to mean the person does not get killed contradicts the statement–“Kill those whom I have already killed [11.34]”. Ignorant people think that a person can be killed. They fail to understand that Jiva is similar to Paramatman and thus cannot be killed.