Rico Tice is a solid evangelical with a great track record in converting people, not least through his Christianity Explored course. He's what used to be called a 'muscular Christian' – ex-public school, captain of Bristol University's rugby team, grew up partly in Africa.
He has a straight-down-the-line, uncompromising approach to faith, and it's very powerful. He's a hugely respected figure in evangelical circles, and just the sort of person the archbishop of Canterbury would want on his evangelism task group alongside Amy Orr-Ewing, Andy Croft and the bishop of Burnley.
But he's resigned, he told the GAFCON meeting in Jerusalem, because the vice-chair is the bishop of Liverpool, Paul Bayes, and Bayes is a supporter of same-sex marriage. He said he and Bayes 'have a different religion'.
'It is around whether scripture is authoritative in terms of human sexuality.
'I think it is a great wickedness to tell people who are on the road to destruction that they are not. To tell them that they are safe when it comes to God's wrath when they are not.'
He continued: 'If we have church leaders that are putting people on that road to destruction it is a salvation issue. That is why we have to distance ourselves. That is why I stepped down from the archbishop's commission on evangelism, which I may say was grievous. I wept about it. I was longing to serve and found it a great honour that archbishop Welby had appointed me to that body.'
It's sad to hear such a statement; this was not a decision that cost him nothing. And given his conviction that this is a 'salvation issue', perhaps he had no option.
And here, in a nutshell, is the great divide that has opened between the constituent parts of the Anglican Communion. For many the question really is, are they even members of the same religion? Or has the gulf become so deep and wide that there's no point in pretending any longer that there's that basic common ground? Is gay marriage such a fundamental issue that those who accept it are not Christians, and those who teach its acceptance are 'wicked'?
Are sexually active 'gay Christians' really on the way to hell?
According to Tice, it would seem so. He represents, at considerable personal cost, the logical outworking of this position. If you belong to different religions, you aren't – as most evangelical Anglicans would assume of liberals – fundamentally on the same side. You are opponents, enemies even.
And this is what drives resistance to the 'big tent' approach of the Anglican Communion from organisations like GAFCON and individuals like Tice: it's about who decides what the gospel actually is, and whether the Bible can legitimately be interpreted in a way that allows the validity of same-sex relationships.
For many if not most conservatives, sophisticated re-readings of the text are contemptible efforts to avoid the plain meaning of Scripture in order to accommodate the church to the world. They deny the integrity of the attempt, and these denials have a particular edge to them because it's all about sex. This particular issue, homosexuality, has a remarkably polarising effect that we don't find even in questions about women in leadership, an area where many conservatives have been more relaxed – and where similar sophisticated re-readings have led many to conclude that women can be ministers after all.
No: this issue is about more than learned Bible scholars arguing intensely and subtly about the interpretations of ancient texts. It's visceral; it's about heaven and hell, truth and falsehood, orthodoxy and heresy. In theory, Anglicans ought to be able to agree to disagree. In practice, the omens aren't good.
Follow Mark Woods on Twitter: @RevMarkWoods