I don't think Two Kingdoms advocates need to throw in the towel just yet. A semi-realized eschatology and the resulting two kingdoms framework together serve to provide a context for Sabbath observance that makes sense.
Historian John Muether writes, "[As a] dissident band of resident aliens… with the corporate identity of a disenfranchised and counter-cultural character," the new covenant church desperately needs the Sabbath in order to retain her peculiarity and distinctiveness from the world. Being a religious minority, God’s pilgrim people need to somehow maintain their "'fortress' or 'ghetto' mentalities that insulate them from the contamination of competing and more powerful (i.e. more socially plausible) worldviews." He continues:
"This is precisely what the Sabbath does [for God’s covenant people]: it enables them to live out their convictions in the context of fellow believers, providing the social support for their 'otherworldly,' or heavenly, citizenship. Put another way, a counter-cultural identity and the practice of the Sabbath become mutually reinforcing."
The corporate assembling of God’s people for worship on the Lord’s day, together with their refusal on this day to participate in the culture they affirm Monday through Saturday, is their way of testifying to the culture that they do not march to the beat of the world’s drum or organize their lives around the world’s notion of "the weekend." This sort of observance, writes Michael Horton,
"... would be a witness to the world that we are not slaves in Egypt, in bondage to the priorities of a greedy culture of marketing and entertainment…. As we refuse to surrender this day to the tyranny of the clock and the gods who amuse us, we enjoy a foretaste of heaven and also proclaim to the world that God is our refuge."Thoughts?