The ‘trajectory’ argument, briefly, is that there are certain practices (such as slavery) that are permitted in Scripture, but it is Scripture itself which sows the seeds of their eventual abolition.  Conversely, there are certain practices (such as same-sex relations) that are forbidden in Scripture, but it is Scripture itself which sows the seeds of their acceptance.

The Bishop of Bangor in the Church in Wales, Andy John, has invoked such a trajectory argument in his support of marriage for homosexual couples.

Bishop Andy John seeks to apply Jesus’ ‘litmus test’: “By their fruits you will know them” (the Bishop references Matthew 5:16f, but he surely means Matthew 7:16f).  If (goes the argument) we can discern the fruit of the Spirit in a person’s life, then who are we to condemn that person’s lifestyle?

And if (Bishop Andy John goes on to suggest) we can see the penny drop within the pages of the New Testament itself with regard to the inclusion of the Gentiles (Acts 10, 15), then we can expect more to coins to fall into place as the church moves beyond New Testament times.

The Bishop acknowledges that the NT is robust in its prohibition of leadership roles to women in the church.  But (he says) this is to be understood in the light of the political and cultural background of the time.  The New Testament is a work in progress: the very liberties recognised by Paul in Col 2:20f are denied by James in Acts 15:20-21.

Bishop Andy John concludes: ‘I have come to believe that the Church should now fully include without distinction those who commit to permanent loving unions with a person of the same sex. I further believe that the best way to do this is for the Church to marry these people as we do with men and women.’

Will Jones comments: ‘The core of the argument is the contention that in certain other matters – slavery, women, divorce, usury, cosmology – the church no longer follows the plain meaning of scripture…However, this development of doctrine away from the plain teaching of scripture is, the argument runs, itself grounded in and mandated by scripture, so scriptural authority is not thereby abandoned.

As Will Jones observes, to subsume same-sex marriage and the same rubric as acceptance of Gentiles, slavery, divorce, usary and cosmology is to confuse things that differ.

Regarding the inclusion of Gentiles, it is clear that this was foreshadowed both in Old Testament prophecy and in the teaching of Jesus himself.

With regard to the teaching of James and Paul on the eating of meat of strangled animals it is apparent that ban of the Jerusalem council was out of consideration for the consciences of Jewish Christians (such consideration also being a theme of Paul’s teaching in Romans 14).

The situation is a little more complex with regard to slavery.  But abolitionists appealed to Scripture itself (and not to some supposed extrapolation from Scripture) and did not find themselves in conflict with any Scripture that approved of slavery.  To the contrary, Scripture repeatedly recognises the enslaved condition to be one from which God rescues people.  The case is very different with respect to homosexuality, where the prohibitions are clear and specific.  Same-sex relations are never represented in a positive light.

Jones cites the following passages:

• In Exodus 21:2 and Leviticus 25:39-46 there is a ban on enslaving fellow Hebrews and a requirement to free any slaves injured through punishment (see also Jeremiah 34:8-22).
• In 1 Corinthians 7:23 Paul teaches that Christians ought not to become slaves, for ‘you were bought with a price’.
• In Colossians 3:11 there is taught the revolutionary basic equality of slave and free in Christ.
• 1 Tim 1:10 includes slave trading in a list of sinful practices.
• Philemon 1:16 mentions an apostolic request to free a runaway slave and treat him as a brother.