If a wicked man can become a pure religious man, this according to Buddhism, is a practical miracle.
In every religion we hear of miracles being performed by either the founders of these religious or by some of their disciples. In the case of the Buddha, miracles occurred from the day of His birth until His passing away into Nibbana. Many of the psychic powers (so-called miraculous powers in other religions) of the Buddha were attained through His long and intense training in meditation. The Buddha meditated and passed through all the highest stages of contemplation that culminated in pure self-possession and wisdom. Such attainments through meditation are considered nothing miraculous but fall within the power of any trained ascetic.
Using meditation on the night of His Enlightenment, there arose within the Buddha a vision of His previous births, the many existences with all their details, He remembered His previous births and how He had made use of these births to gain His Enlightenment. Then the Buddha had a second and wider vision in which He saw the whole universe as a system of Kamma and Rebirth. He saw the universe made up of beings that were noble and wicked, happy and unhappy. He saw them all continually 'passing away according to their deed', leaving one form of existence and taking shape in another. Finally, He understood the nature of Suffering, the cessation of Suffering and the Path that leads to the cessation of Suffering. Then a third vision arose within the Buddha. He realized that He was completely free from all bondages, human or divine. He realized that He had done what had to be done. He realized He had no more re-birth to go through because He was living with His final body. This knowledge destroyed all ignorance, all darkness, and light arose within Him. Such is the psychic power and the wisdom that arose within the Buddha as He sat meditating under the Bodhi tree.
The Buddha had a natural birth; He lived in a normal way. But He was an extraordinary man, as far as His Enlightenment was concerned. Those who have not learnt to appreciate His Supreme Wisdom try to explain His greatness by peeping into His life and looking for miracles. However, the Buddha's Supreme Enlightenment is more than enough for us to understand His greatness. There is no need to show His greatness by introducing any miraculous power.
The Buddha knew of the power that could be developed by training the human mind. He also knew that His disciples could acquire such powers through mental development. Thus the Buddha advised them not to exercise such psychic power in order to convert less intelligent people. He was referring to the 'miraculous' power to walk on water, to exorcise spirits, raise the dead and perform the so-called supernormal practices. He was also referring to the 'miracles of prophesy' such as thought-reading, soothe-saying, fortune-telling, and so on. When the uneducated believers see the performance of such powers, their faith deepens. But the nominal converts who are attracted to a religion because of these powers embrace a faith, not because they realize the truth, but because they harbor hallucinations. Besides, some people may pass remarks that these miracles are due to certain charms. In drawing people to listen to the Dhamma, the Buddha appealed to their reasoning power.
The following story illustrates the Buddha's attitude towards miraculous powers. One day the Buddha met an ascetic who sat by the bank of a river. This ascetic had practised austerities for 25 years. The Buddha asked him what he had received for all his labour. The ascetic proudly replied that, now at last, he could cross the river by walking on the water. The Buddha pointed out that this gain was insignificant for all the years of labour, since he could cross the river using a ferry for one penny!
In certain religions, a man's miraculous performance can help him to become a saint. But in Buddhism, miracles can be a hindrance for a person to attain sainthood, which is a gradual personal attainment and individual concern. Each person himself must work for his sainthood through self-purification and no one else can make another person a saint.
The Buddha says that a person can gain miraculous power without gaining spiritual power. He teaches us that if we first gain spiritual power, then we automatically receive the miraculous or psychic powers too. But if we develop miraculous powers without spiritual development, then we are in danger. We can misuse this power for worldly gain(Pataligama-Udana). There are many who have deviated from the right path by using their miraculous powers without having any spiritual development. Many people who are supposed to have obtained some miraculous powers succumbed to the vain glory of obtaining some worldly gain.
Many so-called miracles talked about by people are merely imaginations and hallucinations created by their own minds due to a lack of understanding of things as they truly are. All these miracles remain as miracles as long as people fail to know what these powers really are.
The Buddha also expressly forbade His disciples to use miracles to prove the superiority of His teachings. On one occasion He said that the use of miracles to gain converts was like using dancing girls to tempt people to do something. Anyone with the proper mental training can perform miracles because they are simply an expression of mind over matter.
According to the Buddha, the miracle of realization is a real miracle. When a murderer, thief, terrorist, drunkard, or adulterer is made to realize that what he had been doing is wrong and gives up his bad, immoral and harmful way of life, this change can be regarded as a miracle. The change for the better arising from an understanding of Dhamma is the highest miracle that any man can perform.
Source : www.ic.sunysb.edu