This teaching is on the deity called Arya Tara. If we examine the nature of Arya Tara from the point of what is called the definitive meaning, the true meaning, then she is Yum Chen Mo - the Great Mother.
Arya Tara is called the Great Mother because she embodies the ultimate meaning of dharma, the ultimate meaning of emptiness - the dharmakaya. It is the source from which buddhas obtain enlightenment and bodhisattvas obtain realization. The dharmakaya is what gives rise to, or gives birth to all buddhas and bodhisattvas.
Green Tara or Dolma is often known as the great liberator who rescues beings from the eight great fears aroused by elephants, lions, snakes, robbers, fire, water, demons and the government. She is one the bodhisattvas that Avalokiteshvara created from a drop of his tear.
On paintings Green Tara is usually seated in a playful posture. Her right hand is in the Varadamudra because she is quick to respond to the petitions of those who seek her aid. She is adorned with five jewels symbolizing the Dhyani Five Buddhas. In both her hands she is holding utpala flowers, symbolizing her purity. Her color is green because her bodhisattva activity is swift like the wind element.