It was subsequently ​passed on to Fairfax Media by sources concerned about the influence of the conservative Sydney diocese on the church. The document was issued by the senior Sydney Bishop Michael Stead, the chairman of the Archbishop's Plebiscite taskforce on gay marriage, who described ​same-sex marriage as "a long way from the good picture of marriage given to us by Jesus and the Bible."​

Early on Wednesday the Sydney Synod released the document, citing polling saying only 8 per cent of Anglicans supported gay marriages in churches.

Bishop Stead said the booklet would be "moderate and reasonable and non-defensive, and not narky or hysterical."

The booklet suggests that if confronted by the argument that marriage has changed before -- such as the 1975 introduction of no-fault divorce -- its members should argue that such changes have not always been for the better.

"The legal institution of marriage in Australia changed at that point and the result has been widespread infidelity and divorce. And this has come at a big cost -- emotional, psychological and economic.

"We opposed those legal changes then, and we've been shown right to have done so. In the same way, we oppose the idea of "open" marriages (non-monogamous marriages), "throuples" (polyamorous marriages) and "same-sex marriages" today."​

The leaked booklet also cites child marriage and relationships between relatives as a reason for resisting change.

"Even those pushing for same-sex marriage would not want marriage opened to children or close relatives or more than two people," the document states.

If faced by the claim that same-sex marriage is "inevitable​", the booklet suggests members cite the rise and fall of​ communism as an example of where resistance to social trends has prevailed.

"In the 1920s progressives proclaimed communism was inevitable in Australia. Then in the 1950s conservatives said a war on communism was inevitable. As it turned out, they were both wrong," the document says.

"No one knows the future. In the Asia-Pacific only one country (New Zealand) has introduced same-sex marriage. We're hearing about it a lot because of what the Supreme Court decided in the United States. But we don't have to go the way of America."

Insisting the Anglican Church is for equality, the booklet claims: "equality is not found in the removal of gender diversity in marriage...all that does is devalue someone's gender.

"It advises opponents of same-sex marriage who feel "silenced" by supporters of change that they could be confronting bigots. "If you ever feel silenced because of your view, it may be the other person who is being the bigot," the church says.​​

If faced with the issue of whether the public debate could lead to youth suicide, the pamphlet advises them to use respectful language, similar to that once used by Senator Penny Wong.

"When Senator Penny Wong previously spoke in favour of the traditional definition of marriage (she has since changed her mind) she chose the following words: "On the issue of marriage I think the reality is there is a cultural, religious, historical view around that which we have to respect". These are calm, respectful words. "

"They certainly aren't homophobic, given that she is a lesbian woman herself," the document says.

This week same-sex marriage advocates warned the government's draft legislation could enshrine discrimination by allowing non-religious marriage celebrants to refuse to marry same-sex couples on "conscientious grounds." The same draft bill also would make it legal for a religious business to refuse gay couples services and venues to celebrate their relationship.

The Labor Party this week formally announced it would not support the Coalition's plans for a plebiscite following leader Bill Shorten's warnings that a public debate about gay marriage could cause LGBTI teenagers to commit suicide.

The Church dismissed these fears.

"There is no evidence that public discussions overseas have led to an increase in LGBTI youth suicide.

"The Irish referendum points in the opposite direction, with the overall suicide rate falling in 2014-2015. LGBTI youth have nothing to fear from a respectful public discussion about same-sex marriage."

Here is a draft copy of the statement:
http://www.virtueonline.org/dropbox/images/2016/10-October/WhatHasGodJoinedTogether%20(SYNOD%20DRAFT).pdf