#89. Since every thought enters the heart through imagining something sensory ( and the sensory hinders the mental), so the light of the Deity begins to illumine the mind only when it is freed of everything and is totally empty of form (without representation of shape or form). For this illumination is manifested in a mind already pure, on condition that it is free of all thoughts.
from Hesychius of Jerusalem, to Theodulus Texts on Sobriety and Prayer.