Well, the answer can be derived via Etymology. Doubt was so in the first instance... but through History I saw that all the greats have prescribed that as the greatest weapon to counteract all frailties.

The beat example was MK Gandhi... He was prescribed to chant Ram Naam (I guess it was Sri Ram Jai Ram Jai Jai Ram) by his lady cook when still a Kid..
He did so and he later admitted that it was not for a long duree.
But He later on said.. it is the only exact science for self realisation.
{Please read "The story of my experiments with Truth" for further clarifications}
Those who took the Name of God, believed not in forcing others to accept their doctrine but do the good even for the meanest crap.