भयाद्रणादुपरतं मंस्यन्ते त्वां महारथा: |
येषां च त्वं बहुमतो भूत्वा यास्यसि लाघवम् || 35||
The mighty warriors will consider that you ran away from the battlefield out of fear and for those whom you have been held in great esteem, will lose their respect for you.
The unwilling Arjuna is ready to withdraw from the battle out of compassion for his friends and family.
However, Bhagwan Shri Krishna points out to Arjuna that if he decides to retire from the battlefield, the opponents would think that Arjuna is running away from the battle out of fear and not due to compassion or attachment to them.
The mighty warriors respect Arjuna due to the immense power that he wields or the numerous battles that he has won in the past. Arjuna has even defeated mighty celestial warriors and that is why everyone respected him for the fighting skills.
Bhagwan Shri Krishna points out to Arjuna that if he withdraws from the fight, no matter the reason, those mighty warriors, who holds him in great esteem, would lose all the respect due to the fact that they will think that Arjuna is running away from the battle due to the fear.
So, to avoid being considered a coward by the mighty warriors, Bhagwan Shri Krishna points out to Arjuna that he should fight this war.