A Greek-English Lexicon of the New Testament and Other Early Christian Literature, is also known as BDAG from the authors initials. This is the top of the line Greek lexicon in existence today and my go to study tool for word definitions. The lexicon gives you an extensive list of how New Testament words are used not only in the New Testament, but in the Greek literature of biblical times. Semantically, words can change meaning depending on time and usage. One of the particular strengths of BDAG is that it gives variations of definitions as a word is used in different verses, so what you end up with is the correct contextual definition. Sell all that you have and buy this gold mine of a resource!
A Greek-English Lexicon of the New Testament and Other Early Christian Literature, 3rd Edition (University of Chicago Press, 2001)
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