While meditation on the personal and impersonal aspects of God requires withdrawal of consciousness into the sanctuary of one’s own heart, concentration on the universal aspect of God is best achieved through selfless service for humanity.
When a person is completely absorbed in the service of humanity, he is completely oblivious of his own body or mind or their functions, as in meditation; and therefore new sanskaras are not formed.
Further, the old sanskaras that bind the mind are shattered and dispersed. Since the individual is now centering his attention and interest not upon his own good but upon the good of others, the nucleus of the ego is deprived of its nourishing energy.
Selfless service is therefore one of the best methods of diverting and sublimating the energy locked up in the binding sanskaras.
Selfless service is accomplished when there is not the slightest thought of reward or result, and when there is complete disregard of one’s own comfort or convenience or the possibility of being misunderstood.
Selfless service is completely achieved only when an individual derives the same happiness in serving others as in being served himself.
The ideal of selfless service frees him from the sanskaras of craving for power and possession, of self-pity and jealousy, of evil deeds actuated through selfishness.
– Extracted from the Discourses 7th ed., pp53-54