The Imitation of Christ, by Thomas a Kempis, tr. by William Benham , at sacred-texts.com
Avoid as far as thou canst the tumult of men; for talk concerning worldly things, though it be innocently undertaken, is a hindrance, so quickly are we led captive and defiled by vanity. Many a time I wish that I had held my peace, and had not gone amongst men. But why do we talk and gossip so continually, seeing that we so rarely resume our silence without some hurt done to our conscience? We like talking so much because we hope by our conversations to gain some mutual comfort, and because we seek to refresh our wearied spirits by variety of thoughts. And we very willingly talk and think of those things which we love or desire, or else of those which we most dislike.
2. But alas! it is often to no purpose and in vain. For this outward consolation is no small hindrance to the inner comfort which cometh from God. Therefore must we watch and pray that time pass not idly away. If it be right and desirable for thee to speak, speak things which are to edification. Evil custom and neglect of our real profit tend much to make us heedless of watching over our lips. Nevertheless, devout conversation on spiritual things helpeth not a little to spiritual progress, most of all where those of kindred mind and spirit find their ground of fellowship in God.