How do we account for the contrast between the OT's preoccupation with hard work, harvests, politics, and justice, and the NT's urging to get our eyes on things above, to live as exiles, to labor for eternal fruit, and store imperishable treasure? Without trying to jam both Testaments into the same mold, I don't think the differences are as drastic as they may seem.
Certainly there is discontinuity in God's plan of salvation from Old to New. But it's wrong to imagine a false discontinuity that envisions Israel's salvation as an earthly utopia and the church's as a heavenly one. There is no such naive idealism in the OT. From Abraham's doubts and white lies to Israel's grumblings and golden calves to the Law's depressing prediction of absolute failure and punishment, the Scriptures stand witness to the blatant shortcomings of the people of God. At best, men and women of faith are fed shadowy images of better things to come. Hebrews 11 offers us a window into a "dualism" older than Israel and its practical implications.
This parade of exemplary saints from Abel to David all demonstrate one thing - commendation of hopeful faith embodied in earthly action. These were not OT caricatures pouring themselves into building heaven on earth. In the Promised Land itself, Abraham was "like a stranger in a foreign country"! No, at their best they were looking forward, seeing from a distance, welcoming "a better country - a heavenly one". Their sacrificial offerings, boat building, baby making, civil disobedience, prophesying, conquering, and administering justice all economically, socially, religiously, and politically served the same purpose - banking their physical lives on something better to come; living a heavenly reality in earthly bodies and communities.
As Christians we look back on a rich inheritance of ancestral witnesses. We look forward to Jesus, whose own obedience meant flesh, blood, work, sweat, connecting the theological dots of worship within our bodily existence, and then dying and resurrecting bodily himself. This "race marked out for us" is tied taut between these examples. No wonder the fledgling church of Acts is instantly forced to define social structures (1:14-15), property rights (2:44-45), politics (4:19; 5:29), and treatment of the poor (4:34) in light of Jesus' resurrection and their mission in the opening chapters. The church is at its worst when it hangs limply in the balance of an aritificial dualism, affirming Jesus' lordship over everything we can't see and having trouble finding his relevance in things that matter.