It’s refreshing, at least. Political careers usually end with electoral rejection, or with the fear of electoral rejection, or with scandal or exhaustion or illness. Politicians rarely come a cropper because of some words from a book last updated 2,000-odd years ago.

And yet that is the position in which we find ourselves in respect of Tim Farron. He has resigned as leader of the Liberal Democrats solely, it appears, because of his views on the sinfulness or otherwise of gay sex. To some, this may make a welcome change: a politician putting principle before power. But to me, it is a failure just as great, and in its own way just as sad, as any in which political careers have tended to end.

The unfortunate failure in Farron’s case is in an apparent misunderstanding of the very faith he proclaims. His resignation statement is remarkable in its claim that Christianity is an enemy of progressive politics: “To be a political leader – especially of a progressive, liberal party in 2017 – and to live as a committed Christian, to hold faithfully to the Bible’s teaching, has felt impossible for me.”

Two things are troubling here: a lack of recognition that Christianity and progressive politics can work together beautifully; and he implies there is only one way to live as a committed Christian, and that way is defined by attitudes to sexuality.

It is hard to see the teachings and message of Jesus in any way that is contrary to the aims of progressive politics. There is his favouring of the peacemakers over the warmongers, the poor over the rich, the powerless over the powerful; his injunctions to feed the hungry, give shelter to the homeless, set free the oppressed; his emphasis on mercy and forgiveness; his care for the sick and those cast out by the rest of society.

If Jesus is at odds with progressive aims, it is because he is more radical and revolutionary, not more conservative. It may well be impossible to be a leader of a regressive, illiberal party and hold faithfully to the teachings of Jesus – I’d like to see Theresa May explain that one away – but it ought not to be any problem at all for the leader of the Liberal Democrats.

Which leads to the rather worrying conclusion that it is indeed homosexuality – alluded to in barely a handful of verses in the Bible and even then in often ambiguous ways – which is at the root of Farron’s torment. He does not explicitly say as much in his statement, but he does mention how, “at the start of this election, I found myself under scrutiny again – asked about matters to do with my faith”.

Now, I may have missed the questions concerning his views on the doctrine of the Trinity, or his take on transubstantiation or the concept of substitutionary atonement, but it seems pretty clear he’s talking about gay sex. Farron’s views on homosexuality also happen to be the issue about which Lord Paddick resigned yesterday.

Farron talks about holding faithfully to the Bible’s supposed teachings. Yes, there is homophobia in the Bible. There’s misogyny too; there are also parts that celebrate violence. But to say that the Bible actively teaches these things is misleading. The Bible is an anthology of books that reflects the preoccupations of its many writers, and the different ways in which they understood the idea of God. Unless Farron goes so far as to believe it is all written by God, then all bar the teachings of Jesus is up for debate and to be questioned and grappled with, as theologians, scholars and ordinary believers have done for centuries.

This has obviously been a difficult time for Farron and he is, of course, entitled to hold whatever views he may. Being a true liberal, he is “passionate about defending the rights and liberties of people who believe different things to me”. And he correctly says that the imposition of Christian tenets on society is counterproductive to the spreading of the gospel. But it seems he fails to appreciate the damage that can be caused by the distinction he draws. Setting Christianity in opposition to progressive causes serves only to undermine the very faith he has resigned in order to uphold.

Farron’s resignation statement ends with the final line of the hymn When I Survey the Wondrous Cross. It’s a hymn I cherish in my heart too, because, every Good Friday, it leaves me broken. But it is a pity he did not include the penultimate line. For what is it that “demands my heart, my life, my all”? It’s not the Bible. It’s not even Christianity. No, it’s something of infinitely greater value: “Love so amazing, so divine.” There is something tragic in all this: Farron appears to think he cannot live as a committed Christian without seeing gay sex as sinful. Tim, you can. Please don’t let anyone tell you otherwise.