Cross-references may be the most abused practice in Bible study. Sure, some are helpful. When a New Testament author quotes an Old Testament passage, it’s convenient to know the reference apart from reading all 37 books to find it. Likewise, when the same event is described in multiple places, sometimes those additional perspectives increase understanding.
However, not all cross-references are created equal. Just because a similar phrase or idea is found in two or more places does not necessarily mean that both places are related. Cross-references were added by someone else, meaning cross-references are not inspired. In fact, they may hinder a person rather than help a person rightly divide his copy of God’s Word, especially if they cause him to move too quickly away from the immediate context.
Unless it’s obvious that the original author intended for his readers to think about another passage of Scripture, we must be cautious. John Calvin said,
Since it is almost (the interpreter’s) only task to unfold the mind of the writer whom he has undertaken to expound, he misses his mark, or at least strays outside his limits, by the extent to which he leads his readers away from the meaning of his author. (quoted in Steve Lawson, The Expository Genius of John Calvin, 70).
Does that mean we should never consider cross-references? Obviously I don’t think that. In terms of contexts, cross-references do fit into the Level 9 circle since they are within the wider context of the Canon. (By the way, I don’t consider it a cross-reference if you’re in the same book/epistle/etc.). But the closer we walk to the paragraph level, the closer we stay to what the original author wanted his original readers to understand.
Let me suggest three lawful uses of cross-references:
- Systematic theology. After meticulous observation in each passage, there is a place to summarize exegesis and outline Scripture’s teaching on a particular subject. [That’s why young theologians are risky. We want someone like John Calvin, and his Institutes of the Christian Religion (1755 OT quotations and 3098 NT quotations), whose theology was refined by “dragging” it through sequential OT and NT exposition for almost 30 years, totaling 21 volumes of commentaries.]
- Analogia Scriptura. Sometimes when exegesis is stuck, we may be helped by studying a clear(er) passage that sheds light on the one that is unclear.
- The Checking Principle. At the end of exegesis (not the beginning), we would be wise to float our conclusions in the broader biblical pool since God’s Word never scuttles itself.
But note, the best uses come after our observation and interpretation of a given passage, or as a last resort when we can’t figure it out. We often run away from our primary passage too soon. Skipping to cross-references too quickly and too often eclipses exegesis; skipping rarely enlightens exegesis.
The Bible-teaching burden doesn’t always require showing people that God’s Word says the same thing twenty times. If God says it once, that one time wields as much divine authority as the other nineteen times. The flow of argument in the near context may make a more powerful case for a truth then a distant cross-reference.
 These thoughts come from the second session of my Rightly | Dividing seminar titled, Surveying Contexts in Bible Study
 Books like The Treasury of Scripture Knowledge, can be helpful, but they can also be deadly if they push a person outside the context.