Prompted by Renee’s comment about the parallels between this self-portrait and images of Christ, I was curious as to why a religious person like Dürer would do something considered to be sacrilegious.  

Amongst other speculations, I thought this article had the most (for me) logical explanation: http://www.everypainterpaintshimself.com/article/duerers_self-portrait_as_christ_15001

Recent scholars have linked Dürer’s portrait to the Imitatio Christi, the idea promoted by St. Francis among others that the good Christian should imitate Christ’s life.

(The link above also reveals other instances of artists depicting themselves as Christ (a lot more overtly), and the website is also a wonderful resource about artists revealing/ representing themselves in their art!)

And http://www.openculture.com/2013/07/the_genius_of_albrecht_durer_revealed_in_four_self-portraits.html, showing the evolution + giving possible readings of his self-portrayals.