Ovid-Metamorphoses

I went to this webpage to read on oved-metamorphoses..
http://larryavisbrown.homestead.com/files/xeno.ovid1.htm
This webpage is quite interesting as it provide a lot of information.
this quotation is taken from there..

Publius Ovidius Naso (43 BC - 18 AD). Ovid seems to have believed in art for pleasure's sake, having no ethical agenda for his writings, unlike his predecessor Virgil, who wrote for the betterment of Romans. Ovid's other works include: Medea (a tragedy, no longer extant), Heroides (letters to legendary heroes from their wives; read them here), The Art of Love (advice on how to seduce a woman; scandalous in Augustus' time, one possible reason for Ovid's banishment in 8 AD), the Fasti (a poetic calendar of religious festivals). Ovid offered something of an apology for his immoral reputation (Tristia 2:354): "My life is respectable, my Muse is full of jesting. A book is not evidence of one's soul."

"My life is respectable, my Muse is full of jesting. A book is not evidence of one's soul."
This line is the line that catches my eyes..a book is not evidence of one's soul..Before this, i have this belief that writers will be writing in what they belief in. this line makes me wonder...is that a statement or just something to cover himself?