Kubera, the god of wealth and the regent of North is also known as Vaishravana and Jambhala. According to Hindu mythology Kubera was the son of a sage called Vishravas, hence his he is also called Vaishravana or Vishravana. He is also the god of wealth and guardian of North in Brahmanical Pantheon. Kubera has both Yi-dam and Dharmapala forms of great antiquity in India and Nepal. As Yi-dam he is called Jambhala, probably from the jambhara (citron or lemon) this form always carries in his right hand. In Tibet Kubera or Vaishravana has been one of the primary protectors of the Gelugpa sect since the fourteenth century. He has two main aspects, that of a warrior protector and that of deity of wealth. As a guardian of the North he is called Vaishravana by Buddhists, and his abode is Alaka in the Himalayas, abounding in wealth and magnificence, where he is attended by Yakshas and horse-headed men called kinnaras. It is believed that performing prosperity rituals to Kubera or Jambhala will increase wealth and prosperity. There is a special ceremony in Tibet for imploring Kubera for riches, which is called Yanyung. Kubera or Vaishravana or Jambhala is popular in Tibet, Mongolia, China, Nepal and Japan where he is known as Bishamon.
In the present Painting Jambhala has been depicted as a god of wealth. The complexion of his body is golden yellow and is semi-wrathful in appearance. The pot-bellied Jambhala is seated in lalitasana on moon disk on a lotus seat. His right foot is pendant and supported by a lotus base. His right hand holds a jambhara. Under his left arm is a large mongoose. The mongoose is supposed to be the receptacle of all gems and jewels, and when Jambhala presses the two sides of the mongoose it vomits the treasures within.
A. Getty, The Gods of Northern Buddhism, Tokyo, 1962
B. Bhattacharyya, The Indian Buddhist Iconography, Calcutta, 1968
Barbara Lipton & Nima D. Ragnubs, Treasures of Tibetan Art, New York, 1996
Ben Meulenbeld, Buddhist Symbolism in Tibetan Thangka, Holland, 2001
Lokesh Chandra, Transcendental Art of Tibet, Delhi, 1996
Marylin M. Rhie & Robert A.F. Thurman, Wisdom and Compassion: The Sacred Art of Tibet New York, 1997
This description is by Dr. Shailendra K. Verma, whose Doctorate thesis is on "Emergence and Evolution of the Buddha Image (From its inception to 8th century A.D.)".