From Scientific American Blog

The Buddha’s Name contains Amitabha’s great compassion, great vow power, and great meritorious virtues. This Name is alive and active, as it has the Buddha’s eyes, ears, and conscience. So, when we recite his Name, Amitabha Buddha can hear it immediately and, in response, appears to protect us, to clear all our karmic obstructions, and to increase our merits and virtues.