The observation and utilization of cross-references in the Bible is a valid and necessary principle of biblical interpretation. Some cross-references may be verbal, others conceptual, and still others because of extended parallel accounts. When used correctly, cross-references can properly inform one another.
There can be a danger, however, in turning the use of cross-references or parallel-passages into its own interpretive approach, or at least in exaggerating it.
Consider these possible dangers of turning this principle into an entire approach.
(1) It is often assumed that this is a biblical method even though the Bible itself never speaks of it.
(2) It can overlook other important interpretive principles that are more primary, such as observing context or grammar.
(3) There is a danger of reading into a text an interpretation drawn from another text. It may even tend to foist some preconceived interpretation from one passage upon another.
(4) It forgets that every passage makes its own contribution first, before it can be correlated with other passages.
(5) It falls prey to the fallacy that similarities must be parallels (Ocam's razor). Interpreters must not assume that because two or more things look similar that they are parallel, or identical.
(6) It wrongly presupposes that the natural reading of a passage is the one that fits best with other passages. It is more correct to conclude that the natural reading of a passage is what fits best with its own context.
(7) It seems to compel interpreters to force scriptural details to fit together rather than to allow each passage to make its own contribution. The systematizing of biblical truth must not be the imposition of a system over the Bible in order to make things fit. Systematic Theology must have large enough categories to allow passages to teach their own truth. This requires new categories to be considered in the compilation of Systematic Theology (for example, "Gentile-ology" and "Israelology" in addition to "Ecclesiology").