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 possible 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
Basil the Great