Advice on Building a Library of New Testament Scholarship
If you want to build a library of New Testament scholarship for your professional use and personal growth, it is wise to remember three things:
First, start a really good Bible dictionary or Encyclopedia. These volumes will introduce you to key issues and offer you guides for further reading. Then buy commentaries on individual Biblical books (and avoid buying commentaries series which often force you to buy the less desirable volumes in order to get the more desirable volumes).
Second, always buy the best books in the field. Usually only a handful of books in any particular area of study set the agenda for the field of study. Read the leaders in the field and avoid derivative scholarship.
Third, always buy books that are beyond your current level of understanding. Buy books that you will grow into, not books that you will grow out of.