In the 35th verse of chapter 2 of Bhagavad Gita for happiness, Lord Krishna tells Arjuna that if he backs out now, people will consider him as a coward. These are the great warriors who've always had a high level of respect for them would not do so. These include many to the Kaurava warriors like Karana, Bheeshma and even Dronacharya. If he backs out now, they would consider Arjuna as a coward.