Comments about the Mandala Offering are given as follows. The actual practice, however, is not described here.
The Two Accumulations
The sublime Nagarjuna has said:
From all such seeds
The fruit appears as a likeness of its cause.
What clever person could ever prove
The existence of a fruit without a seed?
All phenomena exist through the relationship of cause and effect, so the view in which the two truths are inseparable is of fundamental importance. Completing the two accumulations together creates the cause that will produce the absolute body and form body as the result. As the Jewel Garland points out,
Stated briefly, the form body
Arises from the accumulation of merit.
Stated briefly, the absolute body,
O King, is born from the accumulation of wisdom.
It is the accumulation of wisdom (which is included in sustained calm and profound insight as compatible causes) that is the cause for attaining the ultimate result, the absolute body, and that in turn depends on achieving the accumulation of merit. It is said in a sutra:
As long as one has not completed the supreme twin accumulation,
One will not realize supreme emptiness.
Furthermore,
Innate absolute wisdom can only come
As the mark of having accumulated merit and purified obscurations,
And through the blessings of a realized teacher.
Know that those who rely on other means are fools.
The Value of the Mandala Offering
In general, there is an infinite variety of ways to accumulate merit, and they are all included in the practice of generosity and the other transcendent perfections.
However, the offering of the mandala, which is easy to perform and very effective, is the best of all offerings by virtue of the exceptional vastness of its field, attitude, and constituents, and by virtue of its purity:
(1) Its vastness lies in the fact that the field to which one envisages making the offering is not limited but comprises all the Three Jewels and teachers in the ten directions and the three times.
(2) The attitude is impartial, for one is striving for unsurpassable enlightenment and one’s thoughts therefore include all sentient beings filling the whole of space.
(3) The constituents of the offering are unrestricted, their arrangement and form as a Buddhafield that one mentally creates and then offers being as boundless as space.
As for the mandala offering being extremely pure, this is because throughout its preparation, actual practice, and conclusion, it is untainted by such things as the self-centeredness and conceit that can occur, for instance, in making other material offerings. As Lord Atisha says:
Of all the methods for accumulating merit using one’s hands, none have greater merit than the mandala.
Meaning of the Word Mandala
The word mandala refers to a surrounding environment with a central heart, or to something that holds an arrangement of ornaments. In the present context it has the sense of a Buddhafield, for it symbolizes the universe and beings, the support and the supported, all complete and perfect.
Source: Dudjom Rinpoche, Jigdrel Yeshe Dorje. A Torch Lighting the Way to Freedom. Boston and London: Shambhala Publications, 2011.