Christ in the OT

Many OT passages are quite clearly taken up in the NT as preparing for or pointing to Christ. What about those sections of the OT that seem totally unrelated to Christ? What about the proverbs, or the destruction of pagan nations, or long genealogies? I've been wrestling with this recently.

Dennis Johnson provides a paragraph that is extremely helpful here as he concludes his discussion of typology in his 2007 Him We Proclaim: Preaching Christ from All the Scriptures, the fruit of 30 years of teaching NT and homiletics at Westminster (west).

The performance of every covenantal mediator and participant--patriarch, prophet, priest, judge, king, husband, father, son, parents, children, servant--ultimately is to be interpreted in light of the ways it reflects (or falls short of reflecting) the perfect covenant obedience to be offered by Jesus as the Servant of God and the rescue to be accomplished by Jesus as the Lord of his people--in sum, the consummate mediation that would be achieved by Jesus the Son of God and brother of his people. Judges' failings and kings' injustices demonstrated to Israel the need for a coming king who would render justice with absolute equity and divine omniscience (Isa 11:1-5). Priests' pollution and mortality showed Israel the need for a coming priest who would represent the people before the presence of God in unblemished moral purity and permanence. Prophets' sufferings in bringing the message of God reflected for Israel the sufferings of the faithful eschatological Word, but even the prophets on occasion display misgivings and a faltering of faith in the message entrusted to them by God. Thus the mixed behavior of covenantal leaders makes each, by virtue of his office, in one way or another, typological of the Coming Deliverer, in whom the roles of prophet, priest and king would be perfectly fulfilled. (p. 216)