Yellow Jambhala is one of the five Gods of wealth as well as one of the great Dharma Protectors. Although he manifested as a God, he actually is a Tenth-Bhumi Boddisattva who has accomplished all five paths of enlightenment.
When Buddha Shakyamuni was giving the teachings of Maha Prajnaparamita, maras came to obstruct the teaching by collapsing the mountains. While all the rocks were rolling down from the top of the mountains, Yellow Jambhala manifested and used his mighty powers to stop them from falling on Buddha and the students. Afterwards, Buddha Shakyamuni requested Yellow Dzambhala to take refuge with the Three Jewels and become a Dharma Protector who would protect all beings from the suffering of poverty in the future.
According to the Buddhist Scriptures, the practice of Yellow Jambhala will aid practitioners in casting off poverty and economic burdens, and help increase the financial resources needed to practice the path of the Dharma. In order to receive such blessings from Yellow Jambhala, practitioners need to possess supreme Bodhicitta, practice generosity diligently, and accumulate virtuous deeds extensively like a Boddhisattva would. Without these great qualities, the practice will not be effective.
Thus, the practice of Yellow Jambhala helps sincere practitioners develop these qualities and share the merit with all sentient beings.