It had always puzzled me, why God had let polygamy seem to go in the OT!

‘Not his “wives” – but “wife”‘ – I’m sorry but this one doesn’t really support your argument. Deriving meaning from the presence or absence from the plural or not is a stretch too far.

The Matthew 19 passage can be read both ways, the polygamist can argue that as long as he does not divorce his wives, then they all become inseparable parts of his flesh.

It seems to be hinted at in the article, that the polygamist understands the relationship between himself and his wives through the passages (such as Isaiah 54, Revelation 21, 2 Corinthians 11 and several other places in Paul) that describe the Church as a bride for the lamb of God. So does the polygamist see his wives as a church?

If so then he is making a common mistake in biblical interpretation, which is deriving conclusions from the wrong end of the analogy.

An easy way to understand this is to look at Oxes (e.g. Luke 14:5), when Jesus talks about an Ox, it does not mean all Christians need to own an Ox, he is just using it as an example for his wider point.

When Paul says that Christ is the head of the church like a husband is to his wife; Paul is providing insight into the role of Christ using the analogy of the marriage structure of the day; Paul is not saying anything about how one should organise a marriage, men do not have to be the head and the bride is not a plural church (if it was then the polygamist would have men as his wives too).

So what is the right way to approach this topic?

Well for me, the hermeneutical key to understanding the relationship between the Old and the New Testaments is the pericope about wineskins (Mark 2, Matt 9, Luke 5). Once you understand the wineskins then you see there are many related passages in the new testament that work in a similar way.

It is quite clear that Jesus and Paul explicitly deprecate parts of the Old Testament (i.e. the fasting, circumcision, food laws, and so on), while modifying/updating other parts, while keeping a third set the same. So the result is clear, one must put the new wine in the new wineskins i.e. one must not shy away from the newness of the gospel.

Once you accept the newness of the gospel, you understand that all uses of the old testament, must be verified with the new testament. If there is not a passage (or preferably several passages) in the new testament that validate your argument, then you cannot use it. [This leads us to a second hermeneutical key, but I've cut that out because this comment is way too long, we can save that for another comment.]

So in the Old Testament, some patriarchs have multiple wives, while some others have a single wife. Is polygamy validated by the New Testament? No because there is not support for polygamy in the New Testament, and is strongly discouraged by Paul, 1 Timothy 3:2, 1 Timothy 3:12, Titus 1:6 – only one wife at a time.

Note this passage is often misread to mean that divorcees cannot serve, this is not what it says, (εἶναι μιᾶς γυναικὸς ἄνδρα νηφάλιον – he must be the husband of one wife), the NIV’s insertion of ‘but’ is perhaps adds to the confusion, however there is no past meaning in the Greek at all. The idea that divorcees cannot serve also makes very little sense considering the idea of complete forgiveness found elsewhere in Paul.