User blog comment:IamJakuhoRaikoben/Chapter 413: The Book of E.N.D, Review./@comment-2214433-20141222172054/@comment-7418318-20141222173938

Because Gray is being an asshole about it. Instead of either asking Natsu why it's so important not to destroy the book or just going ahead to try to destroy it, he's now repeatedly taunted Natsu to take the book from him.

This is beginning to feel like Gray is more interested in baiting Natsu to fight him than he is in actually destroying the book.