Sanskrit
एतान्न हन्तुमिच्छामि घ्नतोऽपि मधुसूदन । अपि त्रैलोक्यराज्यस्य हेतोः किं नु महीकृते ॥
etān na hantum icchāmi ghnato'pi madhusūdana api trailokyarājyasya hetoḥ kiṃ nu mahīkṛte
Translation
These I do not wish to kill, though myself slain, O Madhusûdana, even for the sake of the kingship of the three worlds; how then for earth?
Annie Besant · The Bhagavad-Gita, translated by Annie Besant (4th ed., 1922) — Wikisource · Public Domain
Explanation
Arjuna pushes the argument to its most extreme form: he wouldn’t kill these relatives even to save his own life, even for rule over all three worlds — so certainly not for a mere kingdom on earth. It’s a rhetorical ceiling, establishing that no stakes, however high, could justify this for him.