Because full moon days are good days to direct the attention to spiritual development.
Buddhists all over the world have a high regard for moon days. In providing an insight into The Moon and Religious Observances his book What Buddhists Believe, the late Dr K Sri Dhammnanda, Chief High Priest of Malaysia and Singapore, said full moon days are celebrated by Buddhists with religious fervor by observing precepts, practising meditation and by keeping away from the sensual worldly life.
“To Buddhists, there is a special religious significance especially on full moon day because certain important and outstanding events connected with the life of Lord Buddha took place on full moon days. The Buddha was born on a full moon day. His renunciation took place on a full moon day. His Enlightenment, the delivery of His first sermon, His passing away into Nibbana and many other important events associated with His life-span of eighty years, occurred on full moon days.”
But it is not just the Buddhists that attach significance to full moon days. Ven Dhammananda said other co-religionists also believe that there is some religious significance related to the various phases of the moon.
It is ancient belief in India that the moon is the controller of the water, and circulating through the universe, it sustains all living creatures. Science, on the other hand, has ascertained that the human body consists about 70 per cent liquid. And it is accepted by physicians that bodily fluids move more freely during full moon.
In view of the possible influence of the moon, ancient sages advised the people to refrain from various commitments on this particular day, take it easy and devote their time to spiritual pursuits.
Ven Dhammananda said all those who have developed their minds to a certain extent can achieve enlightenment since the brain is in an awakened state. Those who have not trained their minds through religious discipline are liable to be subjected to the strong influence of the moon. The Buddha attained His Enlightenment on a full moon day for He had been developing and attuning it correctly for a long period.
Modern science too has its own findings on the influence on the moon on human beings. Medical science has shown that the body has different reactions to certain medicines under different facets of the moon.
Ven Dhammandanda related the story of a nurse who noticed a lot more bleeding occurred when the moon is full. She told the doctor about it but only to be laughed at.
The nurse collecTed records of surgical operations which clearly showed that during full moon, more patients had to be returned to the operating theater than at any other time for treatment for excessively bleeding after operations.
The doctor then started keeping records on his own and he came to a similar conclusion.
“When we consider all those occurrences, we can understand why our ancestors and religious teachers had advised us to change our daily routine and to relax physically and mentally on full moon and new moon days. The practise of religion is the most appropriate method for people to experience mental peace and physical relaxation.,” added Ven Dhammananda