In spite of her subsequent relapse into quietism Madame Guyon accurately described true quiet when she said, "Our activity should consist in endeavouring to acquire and maintain such a state as may be most susceptible of divine impressions, most flexible to all the operations of the Eternal Word."[107] Such concentration can be improved by practice; hence the value of regular meditation and contemplation to those who are in earnest about the spiritual life, the quiet and steady holding in the mind of the thought which it is desired to realize.
Psycho-therapists tell us that, having achieved quiescence, we should rapidly and rythmically, but with intention, repeat the suggestion that we wish to realize; and that the shorter, simpler and more general this verbal formula, the more effective it will be.[108] The spiritual aspect of this law was well understood by the mediaeval mystics.

Thus the author of "The Cloud of Unknowing" says to his disciple, "Fill thy spirit with ghostly meaning of this word Sin, and without any special beholding unto any kind of sin, whether it be venial or deadly.

And cry thus ghostly ever upon one: Sin! Sin! Sin! out! out! out! This ghostly cry is better learned of God by the proof than of any man by word.

For it is best when it is in pure spirit, without special thought or any pronouncing of word.

On the same manner shalt thou do with this little word God: and mean God all, and all God, so that nought work in thy wit and in thy will but only God."[109] Here the directions are exact, and such as any psychologist of the present day might give.