In Sacred history redemption occupies a prominent place, and to deal with redemption without drawing in revelation is not feasible, for as shown above, certain acts are both redemptive and revelatory at the same time.  But the same is true vice versa.  Revelation is so interwoven with redemption that, unless allowed to consider the latter, it would be suspended in the air.  In both cases, therefore, the one must trespass upon the other.  Still logically, although not practically, we are able to draw a distinction as follows:  in reclaiming the world from its state of sin God has to act along two lines of procedure, corresponding to the two spheres in which the destructive influence of sin asserts itself.  These two spheres are the spheres of being and of knowing.  To set the world right in the former, the procedure of redemption is employed; to set it right in the sphere of knowing, the procedure of revelation is used.

-Geerhardus Vos, Biblical Theology, p.15

I love this quote- it shows the necessity of both the acts of Biblical history and how God saved us in our being by that redemptive history, but also the necessity of revelation in order to restore our knowledge.  The two are intimately bound up together, as the revelation shows us the meaning of the redemptive acts, and the redemptive acts are themselves revelatory.