Funny.. I had not really thought about this first vs second born theme in the bible but it does run through it.
Consider also Cain and Able. . Cain the first born kills Able the second born out of jealousy.
Even Adam vs Jesus. . Adam is the first man..and is the root of the fallen man...
A very important insight. Remember that it is not the first birth but being born again that saves! John 3:3