13 When Jesus came to the region of Caesarea Philippi, he asked his disciples, ‘Who do people say the Son of Man is?’ 14 They replied, ‘Some say John the Baptist; others say Elijah; and still others, Jeremiah or one of the prophets.’ 15 ‘But what about you?’ he asked. ‘Who do you say I am?’ 16 Simon Peter answered, ‘You are the Messiah, the Son of the living God.’ 17 Jesus replied, ‘Blessed are you, Simon son of Jonah, for this was not revealed to you by flesh and blood, but by my Father in heaven. 18 And I tell you that you are Peter,[b] and on this rock I will build my church, and the gates of Hades[c] will not overcome it. 19 I will give you the keys of the kingdom of heaven; whatever you bind on earth will be[d] bound in heaven, and whatever you loose on earth will be[e] loosed in heaven.’I take verse 19 to be a delegation of authority from Jesus to Peter (and hence to the church as a whole, the consensus fidelium) on all ethical and moral matters. In other words, the church has the capacity to decide for itself what sort of "social apparatus" to adopt, in the sense that I described earlier.
I see this as underlying decisions like that of the Jerusalem council about whether circumcision was necessary, or keeping the kosher food laws. Those are questions of "social apparatus", and are not matters of salvation. Similarly I believe that the church has the authority to declare gay marriage legitimate, if it so chooses. Underlying this is, of course, an understanding of the authority of Scripture - for a more detailed explanation of my views, see this post.
A teaching of St Paul's is relevant here: "‘I have the right to do anything,’ you say – but not everything is beneficial." In other words, the authority of the church to determine questions of morality is distinct from licentiousness - it still matters what we do, and some things destroy life, other give it. What needs to be attended to are the fruits of the Spirit; or, as is described in Acts, whatever 'seems good to the Holy Spirit and to us'. In order to determine this, there is a right process to be followed, in two parts: the question of truth, and the question of non-judgement, which are the subject of my next two posts.