Amitabha is the Buddha of Infinite Light and one of the Five Dhyani Buddhas. He is the lord of the Western Paradise called Sukhavati, also known as the Land of Bliss or the Pure Land. He is the synthesis of the purity of the maya-body with its appropriate signs in the clarity of mind, which in its essential nature is the same as light. He is the inexpressible luminous essence. He is represented sometimes by himself as a Tathagata. His time of day is sunset, and, as mentioned above, his direction the west. So he is like the setting sun. Setting the sun may suggest the withdrawal of the light consciousness from the world of the senses as it turns within to higher states of meditative concentration. He is the nirmana-kaya, the preparation for the spiritual maturity of his devotees. It is said that before entering Mahaparinirvana, Shakyamuni transmitted to his favorite disciple Shariputra the splendour of Amitabha and his Pure Land Sukhavati. His symbolic syllable is HRIH: H is the sound of breadth, the symbol of all life, R is the sound of fire, I is the intensity of vibration which stands for the highest spiritual activity.
Amitabha is of the nature of conceptualization. Conceptualization proliferates, sparking new ideas, and lording over it is Amitabha. His red colour bears the meaning that compassion is enamored of all of all living beings. The colour of Enamour (raga) is red in the Buddhist tradition. According to the principle of Hatha-yoga, the human personality is adduced into Amitabha’s world by a projection of the conscious principle. In the great splendour of the Pure Land, the devotee can spend aeons in contemplation of Boundless Light preaching the Law.
The practice of the Amitabha sadhana arouses emotional energy, but transmutes mundane passion into Discriminating Wisdom. This is the counterbalance to the Wisdom of Equality of Ratnasambhava, which saw the common factor in all changing appearances. The Wisdom of Amitabha sees the uniqueness, the distinctive characteristics, of every phenomenon. He is very popular in Nepal. The highest devotion is tendered to him at Svayambhu, as he is the Buddha of the present aeon. Bountiful offering are bestowed on him in the western quarter of the Svayambhunath shrine.
Amitabha also has a reflex form – Amitayus. This is depicted here in this statue. The reflex form means certain of the five Dhyani Buddhas can appear in a second form, which demonstrates another aspect of their Wisdom. This second form is sometimes described as the ‘reflex’ of the Buddha. The meaning of Amit is boundless or infinite in Sanskrit and Ayus means life. So Amitayus is the Buddha of infinite life. He is particularly associated with the practices for gaining longevity. We may say that Amitayus is the name given to Amitabha in his character of bestower of longevity.
Amitabha is usually represented holding a pindapatra, Amitayus holds a vase, full of the nectar of immortality. The two figures Infinite Light and Infinite Life clearly represent the same principle viewed from the points of view of space and time, respectively. Indian Buddhism seems to treat Amitabha and Amitayus as the same figure, and it is only in the Tantric Buddhism of Tibet and Japan that one finds them regarded as separate. Even Sadhanamala, has not clearly distinguished them. The Tibetan Buddhist tradition credits the distinctive entity of Amitayus to the Indian teacher Tiphu who revealed it to Ras-chun-grags-pa who diffused his worship in the Land of Snows. In the Japanese tantric denomination of Shingon, Amitayus (Japanese Muryoju) belongs to the Garbhadhatu-mandala and Amitabha (Japanese Amida) to Vajradhatu-mandala. Lokeshchandra, assigned distinction between Amitabha and Amitayus to the seventh century A.D.
The conceptualization of enlightenment as a flash of illumination led to the apotheosis of infinite as Amitabha. An important function of deities is healing and long life. His healing aspect was apotheosized Amitayus. Amitayus Buddha is invoked to cure a person in ill-health, but on death he went to the Paradise of Amitabha, but Amitayus has no specific heaven and he is placed on an abstract plane.
Amitayus Buddha is properly worshipped in Tibet, Mongolia, China, Korea and Japan mainly because of the firm faith of the people in his powers of prolonging life, as the absolute symbols of Infinite (amita) Life (ayus). A sacrament to Amitayus Buddha is celebrated on an auspicious day for life everlasting. Devotees throng to the temple to receive blessings. Every village performs it at least once a year for the life of the community. Many Buddhists commission images of Amitayus Buddha both in sculpture and painting in order to gain merit and assure a long life for themselves or someone else.
This description is by Dr. Shailendra K. Verma. His Doctorate thesis being: “Emergence and Evolution of the Buddha Image (From its inception to 8th century A.D.)”.