Parable of The Koshakara Bird
The Koshakara bird lives inside the trunk of the tree. It bores a hole along the branch and builds its strong nest close to the bark. In order not to leave any room for invasion by any other creature, the bird goes on strengthening the nest on all sides, and leaves absolutely not a pin-hole in it! If it had left a hole it would get air to breathe. But since it is all blocked, for safety, the bird perishes inside.
Similarly, the Grihastha in his anxiety to shut out misery and pain, builds his nest of home and family, of his internal attitude to life, in such a way as to leave no room for any Vritti other than those of sense-indulgence (the material with which his cage is made), to enter his mind. If he had left one small hole of 'Vairagya' in this shell, he would breathe and be enabled to obtain food for the soul in due time. But since he does not allow even this, he perishes miserably within this hard and strong nest.
O man, even if you choose to enter the nest of Grihasthashrama, leave a little hole of 'Vairagya' in it, through which you can escape ' into the Wide World of God-realisation, when the time comes.