Rightly drawing attention to the strongly biblical case mounted and maintained for apartheid in South Africa by Bible believing Reformed Christians, David Runcorn asks the question, "And how do I know when I am wrong? Evangelical Faith and the Bible." We have already had some discussion on David Runcorn's views on homosexuality and the Bible when the Pilling Report was reported on here (he wrote an appendix to the report). I have no wish to rerun that discussion (which issue figures prominently in the article I link to above). Rather, given some past discussion here on Sola Scriptura, I am keen to take up the general question posed in the title, How do I (who believes in the authority of Scripture) know when I am wrong? And making that question have an edge with particular reference to apartheid for which the support of the Bible was once claimed and now it is difficult to find biblical Christians who still support such social policy.
In one way I think the Bible can tell me I have drawn the wrong conclusion from the Bible: I keep reading the Bible, with more depth and more width than previously, and reconsider. I probably (thinking of apartheid's grip on South Africa in the past) need to read the Bible in such a way that my reading opens a cycle of critical assessment of previously reached conclusions (rather than reading the Bible to confirm previously reached conclusions). Of course, if, try as I might, I cannot dislodge the previously reached conclusion then maybe that conclusion stands. In particular, if I read the Bible with others, so "I" becomes "we" then some grounds for thinking the conclusion is correct exist. This was the case with the church in the days of arguments to and fro about orthodox Christology.
Within South Africa those grounds of "we" readers were once thought to exist by the many readers who shared a similar conclusion about biblical support for apartheid. That then raises the question of the width of the community reading the Bible: in those days the rest of the Bible reading world was not supportive of apartheid. Generally the church has recognised that for a conclusion from reading the Bible as God's authoritative Word to be authoritative for the church, the whole worldwide (i.e. catholic) church needs to share that conclusion. (It is not clear to me that David Runcorn recognises that).
Something Protestants likely under-appreciative about authority in the Roman Catholic church is that the Pope's 'Infallibility' relates to one individual giving voice to the reading of Scripture (and Tradition) of the whole church (rather than one individual giving voice to that individual's reading of Scripture).
Protestants may also under-appreciate the difficulties of organising an agreed worldwide conclusion when reading the Bible if we have cast aside the papacy and resisted the possibility of worldwide councils/synods having power over local churches.
Nevertheless a strength of Protestantism (under-appreciated by Romans?) is that over time some conclusions do become agreed around the world (one example of which is, in the present context, that apartheid is wrong). The convoluted process to get there has the virtue of not being affected by the deaths of particular individuals, nor by corruption of officeholders in the church nor by the winds of fashion and favour.
It also has the virtue that it is going to be a biblical conclusion, anchored in the one source of God's revelation that all Christians are agreed is God's revelation to us.
Can the Bible tell me when I am wrong (even about the Bible)? Yes. Likely, however, I will need to listen to what all readers of the Bible are saying rather than what my reading (or even my tribe/clan/wing of the church reading) is saying to me.