From the book "Naam or Word", written by Sant Kirpal Singh

Our mind is ever in a state of oscillation. It is covered with the dust of ages upon ages. All the time our mental faculties are flowing outward into the world, and never for a moment have they known any rest. Until the mind is purified and stilled, one cannot listen to the reverberations of the Sound Current.

There can be no devotion with an unclean mind,
for one cannot have access to the Sound Current,
A man dwelling on the plane of the senses,
dies in the senses and loses all respect here and hereafter.
GURU AMAR DAS

Again,

Oscillating between this and that on account of ego­istic life,
the mind gets lost and finds neither charm nor interest in the Sound Current.
GURU AMAR DAS