From the Life of St Arsenios St Arsenios made it a rule never to discuss things in writing and never to send letters. This was not out of weakness or incapacity – how could it have been, seeing that he could speak eloquently with as much ease as others displayed when speaking in a normal way? But it was due to his long habit of silence and his dislike of self-display. For the same reason he took great care when in church or at any other gathering not to look at other people or to be seen by them; he would stand behind a column or some other obstruction and hide himself from view, remaining unseen and not mixing with others. This holy man and earthly angel acted like this because he too wanted to keep a strict watch on himself and to concentrate his intellect inwardly so that he could raise himself towards God without impediment.
St. Nikiphoros the Monk On Watchfulness and the Guarding of the Heart, Philokalia V4.197