I found a very profound statement in The Bhagavad Gita. I am putting down the English translation here:

In the company of your friend, you lose your centeredness. Your enemy puts you back in your self. Your friend empathises with you and makes you believe in matter. Your enemy makes you feel helpless and takes you to the spirit. So, Your Enemy is your Friend and your Friend is your Enemy.

One who is unfriendly everywhere including to himself – his consciousness is stable and his awareness is established!

~ Krishna to Arjuna during the battle of Mahabharata

I would like to hear your thoughts on this, after reading it.