Several comments have registered discomfort with my (and the WCF’s) narrow construction of the kingdom of Christ. Some in fact have argued that the kingdom extends beyond the church.
I wonder if those who make such claims have considered what this view does to the doctrine of the keys to the kingdom. That doctrine is not explicitly taught in the Westminster Standards but it does come in the confessional tradition from which Kuyperianism sprung. And it takes seriously Christ’s teaching in Mt. 16 and 18 and John 20 that he gave his apostles the keys to the kingdom to forgive sins, to open up the gates of heaven, and to close those gates to those who will not believe and repent.
So if the church has the keys of the kingdom (namely, preaching and discipline according to the Heidelberg Catechism), then why aren’t ministers allowed to hold the keys to the expansive kingdom? Church officers would seem to have some responsibility and authority regarding the kingdom of Christ according to Christ’s own words. But now when the kingdom expands to politics, medicine or aerobics, suddenly those keys don’t work.