We can't be useful to ourselves unless we're useful to others .... Anyone concerned only by his own well-being will suffer eventually. Anyone concerned with the well-being of others takes care of himself without even thinking about it. Even if we decide to remain selfish. Let us be intelligently selfish - let us help others.
Every single being, even those who are hostile to us, is just as afraid of suffering as we are, and seeks happiness in the same way we do. Every person has the same right as we do to be happy and not to suffer. So let's take care of others wholeheartedly, of both our friends and our enemies. This is the basis for true compassion.
Right from the moment of our birth, we are under the care and kindness of our parents, and then later on in our life when we are oppressed by sickness and become old, we are again dependent on the kindness of others. Since at the beginning and end of our lives we are so dependent on other's kindness, how can it be in the middle that we would neglect kindness towards others?
If human beings can be trained for cruelty and greed and a belief in power which comes through hate and fear and force, certainly we can train equally well for greatness and mercy and the power of love which comes because of the strength of the good qualities to be found in the soul of every human being.