What good is it for the religious to shut themselves up in convents and monasteries having little or no contact with the outside world? More than you can even imagine. Assuming, of course, that they are being faithful to their calling, their acts of holiness help us to be holy. How is that so, you may ask? Spirituality ripples out like a stone in a pond. Notice I did not just say "holiness ripples out" or "evil ripples out" because both are true.
When a person does a holy act, with good intention, for the glory of God, then it will ripple out to others; sometimes to those he knows and sometimes to those he does not know, but it will always ripple out. If a mother is living a holy life, it will impact her husband and children, even if they do not know it. This is why the "silent witness" can sometimes be so powerful, and often people do not know why they were led to seek God; someone else's holiness rippled out to them.
So, to be specific, if a religious spends hours in prayer each day (something the rest of us are not usually able to do), that will help others to be able to pray better. If a child seeks to be kind to his siblings, it will help the siblings to be kind to him. In neither of these instances am I referring to the good example of holiness. Although that is a factor, that is mostly on the simple physical level; I am pointing out the invisible level of our behavior and the impact it has on others.
In the same way, if someone goes into a store with a lousy mood, and does not actually express that bad mood to others, he can still impact them because his mood will ripple out. Have you ever been around someone and just felt an uncomfortable "air" to the room; like the atmosphere had changed? It is not necessarily a demonic presence, it could just as easily be the evil in that person's heart rippling out.
Thus, I want each of you to consider the impact you have on others; for good or bad. I want you to realize that since we have been created as physical and spiritual beings, we have a physical and spiritual influence on those around us, and sometimes even on those not around us. What type of stone are you throwing into the pond of your life, and what kind of ripples are going to spread to others?