Originally Posted by Contra_Mundum

I would guess that Vos meant, assuming he wrote a line like this: "it is illegitimate to use later revelation to inform the meaning of earlier revelation," that this maxim would hold exclusively with regard to the doing of BT.

IOW, if you are studying unfolding revelation, you are studying that part of Scripture that was extant at a certain time. Like interpreting Moses, exclusively through the Pentateuch. Or studying what Abraham would know of God by trying to confine oneself to that written revelation he possessed combined with what he was given himself. Likewise, studying David through the Pentateuch, through Joshua, Judges, Ruth, 1&2 Sam, and 1 Chron, plus those Psalms that he wrote (or Moses).

This is a bit of a tricky business, for it is not known what form pre-Mosaic revelation might have taken, nor should we think that everything the prophets ever said was committed to writing. And then there is the light shed by at least some later revelation. Jude, for instance, seems to indicate (not necessarily gathered from OT texts) that Enoch prophesied of the Second Coming. I'm not sure that apart from an inspired Jude, we would have even an inkling from Genesis alone (and only 5 chapters) that Enoch was a preacher of judgment.

In fact, some strict BTers would deny that it is legitimate for Jude to inform us in reconstructing an antediluvian eschatology! We should reject an extreme position like that, while respecting the BT discipline.