Hatred, jealousy and excessive attachment cause suffering and agitation. I feel compassion can help us overcome these disturbances and let us return to a calm state of mind. Compassion is not just being kind to your friend. That involves attachment because it is based on expectation. Compassion is when you do something good without any expectations - based on realizing that "the other person is also just like me".
If there is no other world and there is no fruit and ripening of actions well done or ill done, then here and now in this life I shall be free from hostility, affliction, and anxiety, and I shall live happily.
If the situation was such that there was only one learned lama or genuine practitioner alive, a person whose death would cause the whole of Tibet to lose all hope of keeping its Buddhist way of life, then it is conceivable that in order to protect that one person it might be justified for one or 10 enemies to be eliminated if there was no other way.
So, the tendency of our childish nature is to take small things too seriously and get easily offended, whereas when we are confronted with situations which have long-term consequences, we tend to take things less seriously
When a monk is an arahant, with his fermentations ended - one who has reached fulfillment, done the task, laid down the burden, attained the true goal, totally destroyed the fetter of becoming, and is released through right gnosis - the thought doesn't occur to him that 'There is someone better than me,' or 'There is someone equal to me,' or 'There is someone worse than me.'
When a man is stimulated by his own thoughts, full of desire and dwelling on what is attractive, his craving increases even more. He is making the fetter even stronger. But he who takes pleasure in stilling his thoughts, practising the contemplation of what is repulsive, and remaining recollected, now he will make an end of craving, he will snap the bonds of Mara. His aim is accomplished, he is without fear, rid of craving and without stain. He has removed the arrows of changing existence. This is his last body.
If you cannot find a good companion to walk with, walk alone, like an elephant roaming the jungle. It is better to be alone than to be with those who will hinder your progress.