They were written with such love and such purpose of giving love unto to all the world through the preaching of the teachings of Christ.
In many cases they were written when all that could be done was to send letters in the replacement of the person. Why? Because the writers were imprisoned. In a dark stinking cells with no air to properly circulate the smell of excrement and rot.
Yet the words were written and they were written telling all to spread the teachings of Jesus and Son of God. How do we treat these words these days? We ignore them, pervert them and even teach other fads in their stead.
This is the ultimate insult to those that wrote down these words. It is a critical insult upon the suffering they endured for your salvation.
Peter was hung upside down upon an inverted cross
James was killed with a sword
It is stated that the all but John died of martyrdom. He was exiled and died of old age.