I would definitely be a proponent of sphere sovereignty, so you have me pegged there, but only because I believe it is biblical. I also don’t think Kuyper would have denied that the world can be divided between the Kingdom of God/heaven, and the kingdom of Satan/darkness. I think he would have readily embraced those categories and recognized that there are professing members of the church, who are actually part of the kingdom of darkness, and that the civil government is a mixed bag of both members of the Kingdom of God and the kingdom of Satan. It is not possible to say that anyone who is part of the temporal sphere of the civil government is surely a member of the kingdom of darkness any more than it is possible to say that anyone who is part of the visible church is surely a member of the Kingdom of God.

Now, you seem to be assuming a very different definition of ἐκκλησία than Scripture itself, and then stating that Romans 13 is speaking of the leaders of this voluntary assembly that supposedly referred to a “local body that governed cities in Paul’s day.” However, let us take a look at how Scripture actually uses the term ἐκκλησία.

We could look at how the word was used outside of Scripture, and there you might have a point, since it did refer to the governing bodies of Roman cities. However, we are interested in what Scripture means when it uses that term, and Paul is almost certainly using ἐκκλησία in the same sense as the Septuagint, which was commonly in use at the time of Christ and the writing of the New Testament. Many of the places where the New Testament quotes the Old are direct quotations from the Septuagint.

There are 96 times that the Septuagint uses the term ἐκκλησία. This will already be effectively a long-form note, so we will only look at a sampling to get a good handle on how it is being used.

We see it used in Deuteronomy 4:10, where Moses relates how God had instructed him to “Gather the people to me [at Horeb], that I may let them hear my words, so that they may learn to fear me all the days that they live on the earth, and they may teach their children so.” The word translated to English here as “gather” is ἐκκλησία. To whom is it referring? The leadership of a city or even of the Israelites? No. To the people of God gathered at a particular place; namely Horeb.

Another significant usage we see in Deuteronomy is as part of a phrase, “day of the ἐκκλησία,” which is repeated in Deuteronomy 9:10, 10:4, and 18:16, all of which are referring to when the people of God gathered at Horeb and received the moral law written on tablets of stone.

We also see ἐκκλησία used at the dedication of the temple by Solomon in 1 Kings 8:14, where it says the king “turned around and blessed all the ἐκκλησία of Israel, while all the ἐκκλησία of Israel stood.” Again, we don’t see this term referring to the voluntary leadership of a city, but to the people of God gathered together.

We see the term used by the psalmist in Psalm 22:22, where he says, “I will tell of your name to my brothers; in the midst of the ἐκκλησία I will praise you.” Here ἐκκλησία is referring, as a parallelism, to the psalmist’s brothers, those “who fear the Lord,” who are “the offspring of Jacob,” the “offspring of Israel” (verse23). So again, not referring to the leadership of a city.

When looking at other uses of ἐκκλησία in the Old Testament, it becomes clear that it can refer to any gathering of people together, for good or ill, whether they be people in any kind of authority or not.

With this background in mind, let’s look at the usage of ἐκκλησία in the New Testament and see if any of them support this idea that the voluntary leadership of a city is what is in mind.

We see Jesus himself use the term in Matthew 16:18, when Peter confesses “You are the Christ, the Son of the living God.” Jesus responds saying, “...and I tell you, you are Peter, and on this rock I will build my ἐκκλησία, and the gates of hell shall not prevail against it.” Now, is Jesus speaking merely of a group of leaders, or is he speaking of his people as a whole here? Given how his disciples would have understood the usage of the term ἐκκλησία in the Old Testament, I would wager it is the latter.

We see ἐκκλησία again in Acts 2:47, speaking of the results of Peter’s sermon at Pentecost. Remember, about 3,000 souls were saved as a result of that sermon, and then we see that they devoted themselves to the apostles’ teaching, fellowship, breaking bread, and prayer (verse 42), and other evidences of vibrant faith and love of the brethren (verses 43-47a). The chapter wraps up saying, “And the Lord added to the ἐκκλησία daily such as should be saved.” Who is ἐκκλησία referring to, here? To the 3,000 who came to faith through Peter’s preaching. It is to their number that God was adding daily those who were saved afterward.

In Acts 8:1, it speaks of “great persecution against the ἐκκλησία which was at Jerusalem,” which resulted many early believers scattering “throughout the regions of Judaea and Samaria.” This is most certainly not talking about the leadership of the city of Jerusalem, but rather of the persecution against all of the Christians gathered in Jerusalem.

Again, in Acts 16:5, we see that after Paul and Timothy delivered the decision of the council at Jerusalem (chapter 15) to those in Derbe and Lystra and other cities, “...the ἐκκλησίαι were strengthened in the faith, and they increased in numbers daily.” This is speaking of the Christians gathered in those cities, not the voluntary leadership of those cities, who were often at odds with Paul and his preaching.

How about we get out of Acts and look at how Paul himself used the term ἐκκλησία?

Paul addressed his first letter to the Corinthians saying, “To the ἐκκλησία of God that is in Corinth, to those sanctified in Christ Jesus, called to be saints together with all those who in every place call upon the name of our Lord Jesus Christ…” Was Paul writing to the leadership of this city? No. He specifies that he is writing to all believers in that city, and who are united through their faith to all believers in “every place.”

A particularly interesting usage is in 1 Corinthians 11:18, where Paul says, “In the first place, when you come together as a ἐκκλησία, I hear that there are divisions among you.” Then he goes on to describe how they were dividing by socio-economic class when taking the Lord’s Supper, and treating it as a regular meal, such that some went hungry while others got drunk. This is clearly speaking of coming together for worship when Paul says “when you come together as a ἐκκλησία.”

In Galatians 1:13, Paul confesses that he “persecuted the ἐκκλησία of God.” In Ephesians 5 we see Paul speak of the parallel between husbands and wives and Christ and his ἐκκλησία. In Colossians 4, he encourages the Colossians have the epistle read also in the ἐκκλησία of the Laodiceans. In 1 Thessalonians 2:14 he tells them that they have become “imatators of the ἐκκλησίαι of God in Christ Jesus that are in Judea” by way of their persecution from their own countrymen. In 1 Timothy 3 Paul asks, “if someone does not know how to manage his own household, how will he care for God’s ἐκκλησία?”

In none of these passages is there any indication that Paul is referring to any kind of voluntary leadership of a city, or even just to the leadership of the Christians in a particular place. It always refers to a group of believers who gather together for worship.

Now, let’s see if this definition fits with applying Romans 13 to this group, or even the leaders of this group.

First, Paul refers to those to whom the reader is to submit as “governing authorities” or “higher powers.” The words here are not used anywhere to speak of ecclesiastical leaders. Indeed, one of the only other places we see the word governing/higher (ὑπερέχω) is expressly referring to civil authority, rather than ecclesiastical. 1 Peter 2:13 and 14 says, “Be subject for the Lord’s sake to every human institution, whether it be to the emperor as supreme, or to governors as sent by him to punish those who do evil and to praise those who do good.” This sounds very similar to what Paul is saying in Romans 13, does it not?

The next word Paul uses to refer to those he has in mind is found in verse 3, where he says, “For rulers (ἄρχοντες) are not a terror to good conduct, but to bad.” This term is never used to refer to ecclesiastical leadership, either, but is most commonly translated as ruler, prince, or magistrate.

By contrast, the New Testament uses a couple of terms to refer to ecclesiastical leadership: elder (πρεσβύτερος) and overseer (ἐπίσκοπος). Neither of these terms is anywhere to be found in Romans 13.

Finally, Paul speaks of these higher powers and rulers as “not bearing the sword in vain.” It is assumed by the Apostle that the rulers he speaks of have the authority to use violent force as they carry out their duty. Is the sword something God has given to ecclesiastical leaders? Should the pastor and elders be performing capital punishment? Either we must conclude this is the case, or we must conclude that it is some other form of authority Paul is referring to, and all evidence points to civil authority.

Now, your article rightly points out that civil governments often fail to uphold the purpose for which God ordained them. You have erred in believing this is proof Paul must not be talking about civil authorities, though. It is simply a matter that we only have a duty to obey them in so far as they do uphold this purpose, and we should do what we can to influence them toward that goal, including voting, or even running for office ourselves.