A prison will never be vacant, for there are many prospective criminals who will fill the prison cells, even if the present criminals are freed by the government
“In this way all moving and nonmoving living entities will come into existence, and the entire universe will be filled as it was previously.
While we are preaching, opposing elements sometimes argue, "If all living entities were delivered by the Kṛṣṇa consciousness movement, what would happen then? The universe would be devoid of living entities." In answer to this, we may say that in a prison there are many prisoners, but if one thinks that the prison would be empty if all the prisoners adopted good behavior, he is incorrect. Even if all the prisoners within a jail are freed, other criminals will fill it again. A prison will never be vacant, for there are many prospective criminals who will fill the prison cells, even if the present criminals are freed by the government. As confirmed in the Bhagavad-gītā (13.22), kāraṇaṁ guṇa-saṅgo ‘sya sad-asad-yoni-janmasu: “Because of the living entity's association with material nature, he meets with good and evil among various species.” There are many unmanifested living entities covered by the mode of ignorance who will gradually come to the mode of passion. Most of them will become criminals because of their fruitive activities and again fill the prisons.