When Michael Curry, presiding bishop of the Episcopal Church in the USA, gets up to preach at the wedding of Prince Harry and Meghan Markle this Saturday, he will be speaking to hundreds of millions of people.

Across the world, a huge variety of viewers will be glued to their screens to watch this spectacle of pageantry – something which we in Britain still seem to do pretty well.

Now imagine, for a moment, being in Michael Curry's shoes. What would you say? Why? How would you feel? It must be pretty daunting.

I'm always surprised by how often I hear of weddings (or funerals) where those attending later tell me about their disappointment with the minister. Sadly, the most common complaint is that there wasn't much mention of Jesus. Indeed, I once attended a wedding where the vicar arrived at the sermon slot only to tell the congregation, 'Now is not the time for speeches' – a surprising thing to say with a church-full of visitors. And so there was no talk at all.

Moreover, in this particular situation, with the prospect of addressing a huge international audience, there must be all sorts of temptations which Michael Curry faces, as anyone would. So what should he say? Without wishing to sound in any way presumptuous, here's what I am hoping for:

1. A few jokes. As clergy we don't need to be stand-up comedians. But it is OK I think to make people laugh a bit, especially at a wedding. I sometimes begin a marriage talk with the famous dictum, 'A man isn't complete until he's married; once he's married, he's totally finished.' There's usually a short pause while the penny drops. And then people laugh. A lot. Well, at least, they do when I say it.

2. A focus on Jesus. All of us who preach regularly sometimes feel an instinctive pressure to 'come up with something a bit different' or 'say something new'. But we don't have to. As Christian ministers our task is always and everywhere to preach Jesus Christ, and to proclaim him 'clearly, as we should', to use Paul's words in Colossians. So Michael Curry shouldn't feel any pressure to come up with schmaltzy lines such as, 'this is the stuff of which fairy-tales are made' as Robert Runcie did for Prince Charles and Lady Diana.

Moreover, given that any group of people at a marriage (and, in this case, watching on television) will include a sizeable number of agnostics and atheists, it is a wonderful opportunity to be able to commend Christ in a gracious and thought-provoking way. That's important: over the years, I've noticed an increasing number of what I call 'refuseniks' at weddings – people who stand there refusing to sing, but who choose instead to steadfastly eyeball the minister (me) with what verges on overt hostility, even before I have actually said very much. When the talk comes, it is great to be able to speak gently of Jesus in a way that commends him to them, and hopefully softens their hearts just a little.

3. An explanation of love and marriage. With so many marriages falling apart, and indeed with many people not seeing any need to get married in the first place, it would be wonderful to have even a brief explanation of a Christian view of marriage and of love. I often explain that marriage is not a contract (ie just a bit of paper) but a covenant – a solemn vow between two people to one another in the presence of God and their loved ones, who are thus duty bound to act as their supporters in the years which will follow. In this way it is very different from simply living together. We also sometimes touch on how married love is a commitment ('I will') rather than a fluctuating feeling, and talk about what love means in biblical terms and how Jesus exemplifies this for us.

4. A respect for Justin Welby and the Church of England. The official wedding liturgy of the Church of England states that 'marriage is a gift of God in creation, and a means of his grace, a holy mystery in which man and woman become one flesh', echoing what Jesus says in the gospels on this subject. As a supporter of gay marriage, it might be tempting for Michael Curry to speak in a way which could be perceived as challenging the CofE's official teaching about the male-female nature of marriage. But it would seem ill-advised to put the archbishop of Canterbury in the unenviable position of having to answer questions about whether he agreed with his visiting speaker's sermon. Whatever the arguments for and against gay marriage, there is a time and a place to talk about them, and I would humbly wish to suggest that Saturday's wedding isn't one of them.

It is, of course, presumptuous for me to offer Michael Curry advice. I realise that. But we can all be praying for him. And so let's pray that whatever is said, those watching the wedding will know the truth of St Augustine's words that, whatever our marital status or lack of it, 'You have made us for yourself, O God, and our hearts are restless – until they rest in you.' As a result of Saturday, may we all have an opportunity, somehow, to speak of Jesus.

David Baker is a former daily newspaper journalist now working as an Anglican minister in Sussex, England. Find him on Twitter @Baker_David_A