Intelligent silence is the mother of prayer

Venerable John Climacus ~ The Ladder of Divine Ascent
Step 11 ~ On Talkativeness

¶3. Intelligent silence is the mother of prayer, a recall from captivity, preservation of fire, an overseer of thoughts, a watch against enemies, a prison of mourning, a friend of tears, effective remembrance of death, a depicter of punishment, a delver into judgment, a minister of sorrow, an enemy of freedom of speech, a companion of stillness, an opponent of desire to teach, increase of knowledge, a creator of divine vision, unseen progress, secret ascent.