Q The Church Order (Art. 28a) says that assemblies (synod, classis, council) “shall transact ecclesiastical matters only.” Does that mean they are prevented from addressing climate change or capital punishment or systemic racism?
A It's not that simple. Synod 1937 decided that "political, social, and economic questions are ecclesiastical matters only when doctrinal and ethical issues of sufficient moment and magnitude are involved according to the Word of God and our [confessional] standards." It recognized that there are limits to the church's competence. But it also insisted that the assemblies may touch on such issues when that is warranted.
Take, for example, the system of apartheid in South Africa. The assemblies of the Dutch Reformed Church there were eloquently silent. Those who wanted the assemblies to speak prophetically and correct the wrongs of society were initially told that this was none of the church's business. But they argued that apartheid was out of tune with the church’s creedal foundation that all human beings are created in the image of God. And so, eventually, the tide shifted, and the assemblies declared that any theological justification of apartheid is heresy. Note that they didn't embrace any particular political avenue. They just spoke prophetically and within the realm of their competence.
It is important also in our society today to have the church's voice heard in the marketplace. Our Lord has a claim on every square inch of it. So we address political and societal issues but never bind our people to vote in a certain way when the next election comes around. We must be careful not to politicize the gospel. Yet our assemblies and congregations must be bold in proclaiming it.