Both are needed. Effort till you realize it is the divine itself that is shanti. Till you realize grace and shanti themselves are divine.
This is the error with doing mantra – people make it mechanical. Like the humming of a song or railroad track sound. It happens automatically – even against your will. And that is not the divine.
A mantra becomes effective only if your full attention is on the mantra without diversion. Otherwise it becomes mechanical like a cassette player. Or video. In that case true moksha is attained by your cassette player / or dvd or usb / thumb drive. And since it received liberation go and worship your DVD player!
So don’t become a DVD player mechanical recitation. Full attention is needed. Without a single wayward thought of body or the world.
There are tricks to it. You can’t do it easily
This is from Ramana maharshi
From ~~~ Day by Day with Bhagavan, 17-2-46.
The gentleman said,
“I never thought I was going to have
the good fortune of visiting Bhagavan.
But circumstances have brought me here and I find
in his presence, without any effort on my part,
I am having santi.
Apparently, getting peace does not depend on our effort.
It seems to come only as the result of grace!”
Bhagavan was silent.
Meanwhile, another visitor remarked,
“No. Our effort is also necessary,
though no one can do without grace.”
After some time, Bhagavan remarked,
“Mantra japa, after a time,
leads to a stage
when you become Mantra maya i.e.,
you become that whose name
you have been repeating or chanting.
First you repeat the mantra by mouth;
later you do it mentally.
First, you do this dhyana* with breaks.
Later, you do it without any break.
At that stage you realize you do dhyana
without any effort on your part,
that dhyana is your real nature.
Till then, effort is necessary.”
- Dhyana : Meditation; contemplation
Bhavin