A very useful reference is The Monastic Way, edited by Hannah Ward and Jennifer Wild (Eerdmans, 2006). This is a compendium of brief quotes from monastic writings ranging through the whole of Christian history, arranged as one excerpt for each day of the year. July happens to have some pertinent sayings on the subject of silence. They are found on pp 107-120 of the book.

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Aelred Niespolo, OSB

If the word obsculta [listen: first word of the Rule of Benedict] defines the overall action within monastic life, it is also a part of the message offered to a world that does everything it can in order not to listen. Listening takes place within silence, which is not simply a lack of words, but is a 'counter' to the noise of the world. True silence prevents empty words. One can only listen if one can hear. In the otium [leisure] grounded in silence, and in the 'sacred space' of the monastery itself, God not only speaks to the person, but as importantly, the person speaks with God.

Basil the Great

We must try to keep the mind in quietness. For if the eye is constantly shifting its gaze, one moment this way or that, then veering between upwards and down, it cannot see clearly what lies directly in front of it. It has to bring its gaze to bear on this object so as to see it clearly in focus. In the same way a mind distracted by thousands of worldly concerns cannot possibly bring a steady gaze to bear on the truth...Another image: you cannot write on wax tablets unless everything previously written on them has been erased--and the soul cannot receive godly teaching without first clearing out of the way its own preconceived ideas. With this in view a time of withdrawal is of the greatest benefit, as it calms our compulsive passions and gives reason a clear space to cut them down to size.

Joan Chittister, OSB

Those who cringe from silence see it like the plague, fearful of its weight, cautious of its emptiness and the shock that comes with its revelations. The heaviness and emptiness we feared give way very quickly to turmoil and internal pressure for change. Silence enables us to hear the cacaphony inside ourselves. Being alone with ourselves makes for a demanding presence. We find very quickly that either we must change or we shall surely crumble under the weight of our own dissatisfaction with ourselves, under the awareness of what we could be but are not, under the impulse of what we want to be but have failed to become. Under the din is the raw material of the soul.

Peter-Damian Belisle, OSB Cam

Silence is the language spoken by solitude. Perhaps at first reckoning, we might consider silence merely the absence of sound. But silence is not something that begins only when sound ends. There is something awesome and breathtaking about real silence; it is numinous, pulling us out of our self-containment and calling us towards the invisible. Religious seekers 'home in' on silence as homing pigeons return to their roost, because therein lies the language for personal communication with the sacred.

A Carthusian

There is exterior silence and interior silence. The monastery is, or should be, a place of at least relative silence in the sense of the absence of unnecessary noise and agitated movement. We are less assaulted by harsh sounds; rather we are are soothed by the mostly harmonious sounds of nature, and bells and our Gregorian chant. This pacifies our sensibility and refines it. A heightened awareness is a common experience in solitude and affects all the senses, for they are all linked together. In silence we are more vividly aware of colour, and perfume and touch, because we are more present to ourselves. And little by little, we become attuned to the breathing spaces of silence between the sounds, as it were, like an underlying melody, not exactly 'heard', and yet somehow perceived, something that can take the character of a presence.

Silence begets an attitude of listening; a recollected capacity to receive the manifold communications of being through the doors of the senses, which yet go beyond the sensual to become mediators of a communion of our mind and spirit with what is. The artist, the philosopher, the praying person may perceive or, at least, express in different words diverse aspects of this reality, but all have need of silence, receptivity and awareness.

Peter-Damian Belisle, OSB Cam

People are finding less silence in today's societies. They seek out places of refuge and retreat, hoping for the blessing of mere quiet and, perhaps, sheer silence. They go to monasteries and hermitages so they can learn to listen, or listen more attentively. Within monastic walls, silence is maintained so as not to disturb anyone who may be listening to the Word or simply resting the body. But listening is crucial there, and people recognize that fact instinctively. To what are monastics listening in their silence? To the word of God; to their inner-most hearts; to grace at work in the spirit; to what they discern to be truth--ultimate truth. Here is the place where one is ultimately completely naked--stripped of all pretension and illusion--and where one stands truly as one in the presence of God. Here one stands, simply and utterly, in truth.