The extract from Plato's the Republic is a dialogue taken from the VII, The simile of the cave. In the conversation, Socrates in his role as teacher uses the analogy of the cave to instruct Plato in the art of good government. Socrates uses an analogy to illustrate his idea. This analogy works in the same way as a parable.
The cave represents mans existence and the limited perception in the cave represents mans capacity to understand the nature of his existence. Those who are describes, as prisoners are those whose understanding comes from the senses. The puppet show that posses before them shows the work of human affairs. The view of the prisoners is restricted by habit in the form of a lock.
Socrates states that only those who ascend to the higher realms of the mind into the intelligible region outside the cave and are "released from their bonds and cured of their dilutions" once in the dazzling glare of the sun in the upper world outside the cave the freed man would be able to look at the objects themselves and finally be able to look directly at the "sun itself" The recognisation of the sun as the source of the light rather than the limited light of the fires glare on the wall, the freed man would be thankful for his good fortune. However, if he returned to his old seat of the cave his vision would be dulled and he would be unable to see in the darkness. His fellow inmates of the prison would regard him as mentally unstable and his experience in the upper world as useless.
It seems that in his discourse Socrates is debating that it is to be expected that visionaries will be ridiculed by those who have not seen the source of the light.
In the simile of the cave Plato records Socrates as stating only his own opinion for "the truth of the matter is known only to God" This statement expresses the Platonic idea that human beings can never know the whole truth.
It seems that Plato suggests in his analogy of the cave that it is the philosopher who is able to really have access to and knowledge of the truth. The platonic philosopher believes he is separated from the masses because he is certain of a truth of which the masses are unaware. Plato claims that the philosopher holds a privileged position in his quest for knowledge. This pursuit for something greater than himself is a truth but it is not the universal truth, that is known only to God. The truth the philosopher sees beyond the cave "perceived in the intelligible region is the form of the good" for man the philosopher the good is the highest form of knowledge.
I agree with Plato's point for Christians man is fallible and can only strive to follow the example of Christ.