How could we ever be happy

tasmānnārhā vayaṃ hantuṃ dhārtarāṣṭrānsvabāndhavānsvajanaṃ hi kathaṃ hatvā sukhinaḥ syāma mādhava

So we should not kill Dhritarashtra's sons, our own kin. How could we ever be happy after killing our own people, Madhava?

What it means

Arjuna reaches a conclusion. We should not fight. His reason is simple and human. How could we ever be happy afterwards? He is measuring the choice by the life he'd have to live after it. It's an honest test. Krishna will soon offer a deeper one.

The story

Arjuna calls Krishna Madhava, a tender name. He's no longer arguing law or omens. He's asking a friend to agree that this is unbearable. Krishna still says nothing. He is letting Arjuna empty out every reason before he speaks.

In your life

Think of someone staying in a job they hate because quitting would upset their parents. They ask, how could I face them? A fair question, but not the only one. Ask also, what is mine to do?