(The following is based on the Dhamma article 'Compassionate Goodwill', published in the Vipassana Newsletter, Vipassana Research Institute)
Compassion (karuna) is a very noble, necessary state of the mind.
Like pure selfless love (mettā), sympathetic joy (mudita) and equanimity (upekkha), compassion is also a brahmavihara (sublime state of mind).
But merely talking about compassion, discussing compassion or praising it - all these are far away from true brahmavihara. It is good to accept compassion at the intellectual level as an ideal sublime state. But this is also far away from true brahmavihara.
Brahmavihara means nature of a brahma (the highest being in the order of beings). It is practice of superior qualities, practice of Dhammic qualities. Only when the mind is suffused and overflows with such brahmic qualities can we call it brahmavihara.
The mind can overflow with compassion, mettā, mudita and upekkha, only when one is completely free from impurities at deepest level of the mind. This purity of mind and resulting sublime states are fruits of dedicated practice of Dhamma, i.e. practice of Vipassana to purify the mind.
Life becomes meaningful only when one lives a Dhamma life. A Dhamma life means living a life of morality, that is, to abstain from performing any mental, vocal and physical action that will harm oneself and others.
One needs mastery over the mind to live a life of morality - i.e being free from even evil thoughts of immorality that become seeds for one's harmful actions. The mind should be fully restrained, fully disciplined, not given to blindly reacting to impure impulses.
Gaining mastery over the mind needs ardent practice of concentrating the mind. This can be only achieved with a universal, non-imaginary object of meditation. Such an object of meditation neither generates raga (attachment) nor dosa (aversion). It is based on direct experiential truth and is free from ignorance: such as in Ana-pana meditation, the objective observation of the natural incoming, outgoing breath, as it is.
Why concentrate the mind? This is to sharpen the mind to remove deep-rooted defilements within, by practice of insight meditation, or Vipassana.
With Vipassana practice - i.e, objective observation of impermanent sensations in the body - one develops experiential wisdom (pañña) at depths of the mind. Eradicated by purity of pañña are ingrained negative conditioning and harmful habit-patterns of the mind (sankharas). Sankharas arise from ignorance of blind reactions with craving and aversion, every moment.
The old accumulated sankharas are gradually eradicated with wisdom and purity gained from Vipassana practice. The wisdom is not to react blindly to constantly changing mind-matter phenomena - i.e. the bio-chemical flow of sensations that arise with thoughts. Equanimity is purity. The body is perfectly still during observation of sensations within, making no small movements; the mind is a mere observer of the arising, passing sensations and not reacting with craving or aversion.
The Vipassana practice of equanimity to sensations gradually weakens dangerous negative conditioning in the mind. This is law of nature. Like fire consuming old stock of fuel, the mind consumes accumulated impurities of sankharas when no new fuel of impurities are added each moment.
With correct and consistent practice of Vipassana, the mind is completely freed of all impurities. Then purer mind is naturally filled with the brahmic qualities of mettā, karuna, mudita, and upekkha.
As long as the mind carries the old stock of defilements, and new defilements are added, it is not possible for brahmavihara to arise in the mind.
Ego plays a role in the arising of all defilements.
A ego-centred, self-centred mind may only talk about the four brahmaviharas and praise them highly; but unless one humbly accepts necessity to remove impurities within the mind, and makes all effort to ardently purify the mind, it will not be able to cultivate true brahmavihara.
The purer mind grows stronger in brahmavihara. When a meditator is fully liberated, he dwells continuously in the pure brahmavihara. Therefore, for developing the brahmaviharas of mettā, karuna, mudita, and upekkha, it is absolutely essential to become established in sila, samadhi and pañña.
No individual of any caste, colour, class, society, community or religion has a monopoly on the practice of sila, samadhi and pañña. The practice is universal. Anyone can cultivate them by exerting sufficient effort. One who cultivates them and purifies his mind becomes naturally suffused with love, compassion and goodwill.
The defilements of an impure mind cannot be labeled as Hindu, Muslim, Christian and Jain defilements; similarly love, compassion, goodwill and other wholesome qualities of a pure mind cannot be given any sectarian label. The malady of misery is universal. The remedy too is universal.
Just as the pure Dhamma of sila, samadhi and pañña is universal, eternal, absolute, timeless, so also the brahmaviharas arising from practice are universal, eternal, absolute and timeless.
None of the religious traditions-Hindu, Jain, Sikh, Muslim, Christian, Parsi or Jewish-reject the importance of morality, concentration of mind and purification of mind, and the resultant compassion and goodwill towards all beings.
Different societies, communities and sects have different ways of worship, different places of worship, different rites and rituals, different festivals, different vows and fasting days. Their philosophical beliefs are different. Actually, different communities or sects originate and flourish on the basis of these differences.
But the Dhamma of morality, concentration, wisdom, and love, compassion and goodwill is universal. It is the same for all societies, communities and religions. This universal Dhamma and the resultant compassion unite all religious sects. While continuing to maintain their distinct sectarian features, they can unite at the level of universal Dhamma. All can become one in the practice of the brahmaviharas of love and compassion.
This is why people from all religions, including religious leaders, often say with pleasant surprise after taking a Vipassana course: "Vipassana is only putting to actual practice the teachings of my religion."