'Preach the gospel at all times. And if necessary, use words.'

It's possibly the most often-quoted monastic saying of the modern church. Used rightly to challenge an over-emphasis on proclamation evangelism in certain parts of the church, it has passed into the Christian phrasebook as an almost-Biblical reminder to remember the place of practical acts of love that demonstrate Jesus' love for the world. Attributed to St Francis of Assisi, renowned environmentalist and social justice pioneer and founder of the Franciscan Orders, the phrase has again become popularised among the Insta-quote generation, who love the fact that it a) sounds cool and b) possibly prevents us ever having to have awkward evangelistic conversations.

Yet the quote is also hotly-disputed. A rival school of thought argues that Francis has been misquoted, and that in fact the phrase ended '...and also use words', in order to illustrate the importance of, rather than the total replacement by, deeds-based evangelism. Still more people suggest that Francis' quote is a complete invention, or at least came from a different source. But what's the truth - and perhaps more importantly, is this phrase deserving of all the attention it seems to receive?

Did St Francis say it?

The first question seems surprisingly simple to answer. None of Francis' disciples or biographers appear to attribute this phrase or anything like it to the man himself. He did write, in his Rule of 1221, that 'All the Friars... should preach by their deeds,' but it's widely agreed that this was a rebuke to hypocrisy – against word and deed not matching up to each other – rather than a suggestion that preaching can somehow occur through deeds alone. Writing just three years after his death, Thomas of Celeno attaches this quote to Francis: 'The preacher must first draw from secret prayers what he will later pour out in holy sermons; he must first grow hot within before he speaks words that are in themselves cold.' Francis was concerned with our inner and outer lives matching up, and while he was absolutely concerned with justice and love for the poor, it seems that's not what he was talking about when he wrote about 'preaching by deeds.' He's also quoted as saying, 'It is no use walking anywhere to preach unless our walking is our preaching,' which seems to convey much the same idea.

Did someone say it?

Interestingly, St Francis doesn't have a monopoly on the quote. It's also – astonishingly – been attributed to Mormon President Dieter F. Uchtdorf, who was just misquoting Francis but managed to get in on the attribution thanks to the powers of the internet. So where does the quote actually originate from? The Franciscans themselves widely refuse to attribute the quote to their founder, so it's likely that at some point – probably in the last 100 years – an enthusiastic preacher somewhere simply made the leap in reading and approximating Francis' writing, and the phrase caught on.

Most importantly, is it Biblical?

Loving the poor is absolutely Biblical. Caring for people, seeking justice, and as Francis rightly says, living an honest life free from hypocrisy, are all entirely Biblical. But so, it seems to me, is the idea that the Christian gospel involves hearing as well as seeing; word as well as deed. In Romans 10 v 14, Paul writes: 'How, then, can they call on the one they have not believed in? And how can they believe in the one of whom they have not heard? And how can they hear without someone preaching to them?' It would seem that Paul believed it wasalways necessary to use words. And just in case you prefer to hear things from the horse's mouth, Jesus talks about or demonstrates proclamation often, in Mark 1 v 14-15 and 16 v 15, in Matthew 4 v 17, Luke 3 v 3 and 8 v 1 and on various other occasions. Jesus was the most perfect incarnation of Jesus possible - and yet he still used plenty of words to share the Gospel.

Like all soundbites, the phrase misattributed to St Francis is useful to a point. There are clearly those Christians who have prioritised the speaking of the Gospel so highly that they lack any commitment to demonstrating practically God's love – and of course that was exactly the kind of hypocrisy that St Francis of Assisi wanted urgently to challenge. At the same time, it's a catchy idea with a dangerous fault-line running through it, and while it might be attractive to think we never have to risk the embarrassment of talking out loud about our faith, the Bible seems to suggest it's vital if we truly want to see our friends understand what Jesus has done for them.

So preach the gospel at all times, and however you like... but at some point, we all need to face the discomfort of using some words as part of that.

Martin Saunders is a Contributing Editor for Christian Today and the Deputy CEO of Youthscape. Follow him on Twitter @martinsaunders.