Geerhardus Vos, The Eschatology of the Old Testament, p.7, speaking of Romans 8 says:
This is a longing, a prayer, a beseeching of God that only the redeemed subject of religion can experience. The groaning of the irrational creature is left far behind by it. The Christian alone can experience it and does experience it with such intensity that it became to Paul in itself a prophecy of fulfillment. It is like the craving hunger that knows there must be bread somewhere.
Is anyone else reminded of C.S. Lewis?