76. Those who indulge their passions, being materially-minded, are distracted during prayer by their thoughts as by frogs. Those who restrain their passions are gladdened during prayer by the changing forms of contemplation, which are like nightingales moving from one branch to another. But in the dispassionate there is silence and great quiescence of both thought and intellection during prayer.
Philokalia V3.57 Ilias the Presbyter