Chagdud Gonpa

"In the Vajrayana Buddhist tradition, we accumulate merit in order to create positive short-term circumstances such as health, wealth, and longevity and, more deeply, to reveal our wisdom nature.
What is the meaning of butterlamp offerings? We do not offer butterlamps because enlightened beings need to see them. Rather, the offering of light is a means of dispelling the darkness of our own ignorance, giving rise to clarity and wisdom. We offer them with the wish that their light will illuminate the lower realms and the bardo, assuaging the torment of beings who suffer in darkness. We also aspire that all beings will develop greater mental clarity in order to discover the causes of long-lasting happiness in virtuous actions of body, speech and mind. Finally, we offer them so that the inner light of great knowing will arise in the minds of all beings and remove the darkness of ignorance and intellectual obscurations.

The pure and excellent ones to whom we offer are the Three Jewels -- the Buddha, Dharma and Sangha, who encompass all enlightened beings; the Three Roots -- Guru, Yidam and Dakini; and the dharma protectors.

We exercise great care in offering, for the merit created is dependent upon our pure motivation, visualisation, and proper gathering and preparation of the substances. If everything is done mindfully, our merit increases, as do our positive qualities. On completion of our offering, we dedicate the merit for the benefit of all beings so that this accumulation of virtue cannot be destroyed."
(Khadro Ling, Brazil, 1999)
 
Shakyamuni Buddha mentioned the 10 benefits of light offerings in Tune of Brahma:
One becomes like the light of the world;
One achieves clairvoyance of the pure eye as a human;
One achieves the Deva's eye;
One receives the wisdom to discriminate virtue from non-virtue;
One is able to eliminate the concept of inherent existence;
One receives the illumination of wisdom;
One is reborn as a human or deva;
One receives great enjoyment wealth;
One quickly becomes liberated;
One quickly attains enlightenment;