Studying the Bible topically, i.e. assembling a list of scriptures that bear on a given topic, can be useful, but is vulnerable to abuses and distortions, as in the WT belief system. It seems never to occur to the dubs that the Bible did not drop out of heaven in its present form, subdivided by chapter and verse. This system is relatively recent. It's clear that the books of the Bible were intended to be read as one reads any book, i.e from beginning to end. Context and proportion are almost totally ignored by the JWs as they tread over the same catch-phrase memorized verses time after time, verses which represent probably no more than 5 percent of the total volume of scripture.
Ask any JW for example, what Paul's main message to the Romans was (``salvation by grace, not works) and you're likely to get a blank stare.