Amitabha's mantra is calling the name of Amitabha. Like in the 6 syllable Chenrezig mantra, the 6 syllable Amitabha mantra stands for the 6 Paramitas, the antidote to the 6 afflictive emotions. The mantra has the nature of Bodhichitta.
The 6 Paramitas:
1) The Perfection of Generosity (Dana Paramita)
2) The Perfection of Ethics (Sila Paramita)
3) The Perfection of Patience (Kshanti Paramita)
4) The Perfection of Joyous Effort / Enthusiastic Perseverance (Virya Paramita)
5) The Perfection of Concentration (Dhyana Paramita)
6) The Perfection of Wisdom (Prajna Paramita)
By reciting this mantra, the 6 afflictive emotions are purified and the qualities of the 6 Paramitas are accomplished. We increase our love and compassion and thereby destroy self-grasping.
If the mind is not distracted, you will see the nature of mind. By seeing your true nature, afflictive emotions will disappear. By reciting the mantra mindful awareness and wisdom increase. This wisdom awareness will disperse the afflictive emotions. Once these emotions are gone, the mind itself is the Buddha. There is no need to look for a Buddha elsewhere. Thus the Buddha said, 'perfectly tame your own mind! This is the Buddha's teaching.' To clean up your own mind is the Buddha's teaching.
The seed for Dewachen is already within your mind, your true nature. If the mind remains undistracted, it will be actualized. When self-grasping diminishes, the nature of mind itself is Dewachen. You can go to Dewachen by the power of your own mind. Right now, Dewachen is within your mind, it is the bliss that is your own true nature. If you realize it you will be born in that bliss after parting from this body.
OM AMI DEWA SHRI