Gospel in the OT Historical Books

My impression that the idea that the OT is mainly about sin and judgment comes largely the so-called historical books. While there are a few bright spots, it often seems as though it's mainly sin, sin, and more sin. Even the good guys usually end up sinning.

There is, of course, lots and lots going on in these books. I don't at all think that they're univocal. And there are several large themes going on as well -- the inability of the natural seed to bring the kingdom, a death & resurrection motif, the presence of God in Israel's experience (in light of, and interacting with, the Temple/land structure in the Penteteuch), and lots of other stuff.

But it seems to me that one of the big overarching themes -- and one that makes what we take from the historical books to be gospel rather than judgment -- is captured by Paul in 2 Tm 2.13:

"If we are faithless, he remains faithful, for he cannot deny himself."

Through all of Israel's sin in the historical books, God keeps his promises to Israel; he remains faithful, despite human sin and faithlessness. Ultimately, God's promise resolves into Jesus going to the Cross. (The cross is proof of God's faithfulness, par excellence. A righteous man "swears to his own hurt and does not change his mind" Ps 15.4.) So, in a sense, the worse that Israel is portrayed in the OT, the better news it is -- God remains faithful. We can trust God to do what he says he'll do -- he proved that to us in these books.

I guess we always knew that. That's the point, after all, of all of those comparisons in the prophetic books of Israel to a harlot and God to a faithful husband. The thing is, though, that the historical books are the empirical meat for the prophetic skeleton. God remains faithful to sinners. It's amazing.