Amitabha is a celestial buddha described in the scriptures of the Mahayana school of Buddhism. Amitabha is the principal buddha in the Pure Land sect, a branch of Buddhism practiced mainly in East Asia, while in Vajrayana Amitabha is known for his longevity attribute and the aggregate of distinguishing and the deep awareness of individualities. According to these scriptures, Amitabha possesses infinite merits resulting from good deeds over countless past lives as a bodhisattva named Dharmakara. "Amitabha" is translatable as "Infinite Light," hence Amitabha is often called "The Buddha of Infinite Light."
According to the Larger Sutra of Immeasurable Life (Mahayana Amitayus Sutra) Amitabha was, in very ancient times and possibly in another system of worlds, a monk named Dharmakara. In some versions of the sutra, Dharmakara is described as a former king who, having come into contact with the Buddhist teachings through the buddha Lokesvararaja, renounced his throne. He then resolved to become a buddha and so to come into possession of a buddhaksetra ("buddha-field", a realm existing in the primordial universe outside of ordinary space time, produced by a buddha's merit) possessed of many perfections. These resolutions were expressed in his forty-eight vows, which set out the type of buddha-field Dharmakara aspired to create, the conditions under which beings might be born into that world, and what kind of beings they would be when reborn there.
In the versions of the sutra widely known in China, Vietnam, Korea and Japan, Dharmakara's eighteenth vow was that any being in any universe desiring to be born into Amitabha's Pure Land and calling upon his name even as few as ten times will be guaranteed rebirth there. His nineteenth vow promises that he, together with his bodhisattvas and other blessed Buddhists, will appear before those who call upon him at the moment of death. This openness and acceptance of all kinds of people has made the Pure Land belief one of the major influences in Mahayana Buddhism. Pure Land Buddhism seems to have first become popular in northwest India/Pakistan and Afghanistan, from where it spread to Central Asia and China
The sutra goes on to explain that Amitabha, after accumulating great merit over countless lives, finally achieved buddhahood and is still alive in his land of Sukhavati, whose many virtues and joys are described.
The basic doctrines concerning Amitabha and his vows are found in three canonical Mahayana texts:
Through his efforts, Amitabha created the "Pure Land" called Sukhavati (Sanskrit: "possessing happiness"). Sukhavati is situated in the uttermost west, beyond the bounds of our own world. By the power of his vows, Amitabha has made it possible for all who call upon him to be reborn into this land, there to undergo instruction by him in the dharma and ultimately become bodhisattvas and buddhas in their turn (the ultimate goal of Mahayana Buddhism). From there, these same bodhisattvas and buddhas return to our world to help yet more people.