Why is it that chanting sometimes produces effective result, and at times, it doesn’t?

As an example of how the Shurangama Sutra can help to ward off catastrophes in times of danger, a man was supposed to have drowned after falling into the sea, but having chanted this sutra, the danger was mitigated and the man survived. In another instance, an airplane was supposed to explode while in mid-air, but chanting helped overcome the danger and there was no explosion.

A practitioner has to rely on his own effort to overcome the affliction that exists in his heart, such as the chaotic and wishful thoughts in his mind. With an impure mind filled with distractions and without removing the fundamental annoyances in his heart, merely chanting will not be helpful. It is necessary to purify one’s heart and mind of such distractive thoughts, so that one may achieve lucidity and understanding. Therefore, due diligence in one’s practice is most important.

Extracted from “In Memory of the Venerable Master Hsuan Hua” Vol 3 – the Shurangama Sutr[a

中文解答

Master Sheng Yen discusses the topic on chanting mantras:

The power of mantra comes from the merit attained by a certain ghost, deity, Bodhisattva, or Buddha, as well as from the mental power or power of concentration of the person reciting it. The efficacy of mantras lies in faith.

More from Master Sheng Yen:

The purpose of sutra recitation and mantra chanting
There are two functions of reciting the sutras and mantras. It helps us to self-reflect whether our acts are in accord with the sutras. It is also a meditation practice.