Modelling the growth of the church in times of revival is fraught with difficulties as the work of the Holy Spirit is so unpredictable: “The wind blows where it wishes”, John 3:8. Social modelling of the sort I do in church growth depends on the reaction of people being predictable when large enough numbers are aggregated together. But when the Spirit cannot be predicted, neither can the reaction of those whom He moves. “The wind blows where it wishes …. so it is with everyone who is born of the Spirit”.
Lewis Revival 1949-1953
To illustrate the point, I want to take you back to an incident during the revival on the Isle of Lewis in Scotland that occurred on 1st February 1950 . Duncan Campbell the revivalist told this story of the parish minister of Carloway, Murdo McLennan, who went to a young people’s dance, the nightclub of their day, and sang psalms until the Holy Spirit fell. To quote from one of Campbell’s sermons:
A minister standing there turns to his wife and says, “Look there are the two pipers that were to have played at the concert and dance in our parish tonight. There they are crying to God for mercy. So we'll go home to the parish, and we'll go to the dance, and we'll tell what has happened.”
So off they went. And arrived at the dance about eleven o'clock, the man who met them wasn't at all happy at seeing them there. Why had they come to disturb the night of amusement? But the Parish Minister claimed the right of parish ministers to walk in, and he walked in, and during a lull in the dancing he stepped onto the floor and said, “Young folks, a most remarkable thing has happened in Barvas. You know the pipers that were to be here are crying to God for mercy in Barvas. You advertised that they would be playing, but they're crying to God for mercy.'
And then he said, “Would you sing a Psalm with me?” “Yes”, said a young man, “if you'll lead it yourself”.
So he gave out Psalm 50 where God is depicted as a flame of fire. Also they sang, I think it was at the second verse when the power of God fell on the dance. The schoolmaster, who was at the head of the concert party, cried to God for mercy. Young people fled from the hall, and went to their buses and in the buses they were crying to God. One young boy, the youngest boy saved in the revival, twelve years of age, is now the parish minister of Kinlochbervie. 
Other versions of the account say that it was 3.00-3.30 in the morning when the Spirit fell, and that other psalms were used [1,3]. It is also said that some were the worse for wear because of drink. The hall being used for the dance was next door to the minister’s residence in Carloway, and he and his wife briefly went home to have a cup of tea and pray before entering the dance . He entered the hall though a side door, without paying, which was one of the reasons the dance organizer was not happy with him [4,5,6]!
It turned out all bar three of the people at the dance were converted . They were not all converted at once, but all came under conviction that night and were subsequently converted over the coming days. Such incidents were typical of the Lewis Revival, and many other revivals as well.
Let me try and relate the Carloway incident to my limited enthusiasm model of church growth. The hypothesis behind the model is that there is a sub-group of Christians called enthusiasts whose faith is infectious, and are thus responsible for conversions though contact with unbelievers. Some of those converted unbelievers become enthusiasts who also pass on their faith, and so it continues, as long as enthusiasts keep reproducing themselves. In this case the minister, Murdo McLennan, was clearly the enthusiast. But how exactly did he pass his faith on? How much of what it means to be a Christian was picked up late at night in a dance, under the influence of alcohol, when only a limited message is given, and a psalm, which mentions God, but not Jesus?
The reality is that there is a context. Firstly most people on the Isle of Lewis would have known about Christianity, the shorter catechism of the Westminster Confession was taught in schools. As children they would have most likely attended church, as there was nothing else happening on a Sunday, which was (and still is) a Sabbath in those parts. Thus once under conviction, they would have known where to turn to find peace. Thus the effectiveness of the minister as an enthusiast is heightened by the religious background.
Secondly, there is the knowledge of the revival itself, which although not heard of in much of the UK, would have been very well known to people on the west of the Isle of Lewis. Thus there would have been a fear among unbelievers that they could also be so affected. The mere knowledge of a revival can bring back to mind other things, already heard prior to the meeting, that could all be used by God in the conversion of the person.
Thirdly, there were the pipers, who were known to many of the people there. Their services were called upon all over the island. If they could be converted, what hope was there for those in the dance? However the pipers do not class as enthusiasts in this instance. Their prior conversion sets the context, but it is not the point of contact that brings conversion.
Fourthly, there was the boldness of the minister. He was quite prepared to break all social conventions and challenge people in their own place. One of the main reasons the modern church fails to grow is a lack of boldness.
Fifthly, there is the Holy Spirit, who can bring the things of God into the mind and spirit of a person that were not communicated by any human agent. There was an outpouring of the Spirit on Lewis, a revival, a move of God. Things happen in people’s hearts that cannot be explained by any other means.
Thus in this incident one enthusiast saw scores of people converted, and thus had a massive conversion potential, even if he saw no one else converted in his life . His reproduction potential will have been large as well . We definitely know of one of “his” converts who became an enthusiast, the 12-year-old boy who was converted, who in time became a minister himself and used in revival. Very likely other converts spread the word and saw the fruit of conversion also. In most revivals reproduction potentials are generally between 1 and 2. So how is this one potentially so big?
Ministers, especially a parish one with so many contacts, will see many converts, however ministers are only small in number compared with all the other enthusiasts in a revival. Typically an enthusiast is a person who invites an unbeliever to a meeting, where they get converted, but it is the person who brought them, not the speaker who brings about their conversion, who is the enthusiast in the model. Thus when averaged together the ministers’ reproduction potentials are lost in the figures. However ministers are a very important part of the spread of revival if they can be encouraged, like Murdo McLennan, to keep their face-to-face encounters with unbelievers.
What is unusual about the dance in Carloway is that it is not in a church meeting, or a one-to-one encounter where someone gets “led to the Lord”, but an encounter on “enemy territory” where God uses the boldness of the believer and the background of the people to achieve in one evening what normally takes the church a year! This is where enthusiasts, and especially ministers, are at their most effective. It is wonderfully hard to model as it is impossible to predict the outcome on the basis of the past experiences that are tied up in the averaging process. But strangely enough it is more typical of the type of incidents in the Gospels and the Acts of the Apostles.
So is the church missing something? Should it be attempting, with God’s help, this type of encounter, or is such a thing impossible in our post-Christian and post-modern landscape? (As I write this I can hear the words in my head “Nothing is impossible for God!”)
Well this post did not come about by accident. Only a few weeks ago a Richard Taylor at the Cwmbran Outpouring said he would love to get up in a nightclub when a DJ is playing and sing “Jesus, Jesus…” just to see what would happen .
So is the context that different? There is the boldness of the minister in going into non-religious territory. There would be plenty of converts to go with him, some of whom would be know, or if not known would be their type of people. If this were tried in Cardiff it is unlikely there would be much knowledge of the outpouring among non-churchgoers, but in the area around Cwmbran that knowledge is growing fast. The knowledge of Christianity of course is light compared with the Isle of Lewis, but that will not stop someone coming to Jesus; it just means it will take longer to disciple converts to become more like Him. And of course the Holy Spirit has not changed!
Conversion is ultimately a supernatural act. If God can do it in Carloway in 1950, then he can do it in Wales in 2013. It may take more than a few days to see fully-fledged and converted disciples, perhaps months or years, but it must be worth a go! The whole essence of a move of God is it gives his people boldness to encounter unbelievers outside of the church context. Murdo McLennan was “infected” with the revival when he entered the Carloway dance to sing his psalms back in February 1950, and the infection was caught by the dancers. May we see many Christian singers invade the nightclubs today and take the current Holy contagion with them! Watch the Spirit blow where He wishes!
Church Growth Modelling, churchmodel.org.uk
 Sounds From Heaven, Colin and Mary Peckham, Christian Focus, 2004, pp 48-49.
 The Lewis Revival, taped talk of Duncan Campbell, The Faith Mission, transcribed on a number of websites, such as
 The Lewis Awakening: 1949-1953, Duncan Campbell, The Faith Mission, 1954.
 Duncan Campbell: A Biography, Andrew Woolsey, Hodder & Stoughton, 1974, p136.
 I met one of the converted pipers in 2002 in his house in Upper Siadar on Lewis. He gave his own colorful version of the event, though of course he was not at the dance due to his prior conversion!
 The incident is alluded to in a recent song, The Ballad of the Revival, by Mairi Campbell, granddaughter of Duncan Campbell,
 Revival in the Hebrides, taped talk of Duncan Campbell, 1968, transcribed on a number of websites, such as the Revival Library:
 The Conversion Potential is the number of people one enthusiast would bring to faith, see converted, during their entire enthusiastic period, if all the people they contact were unbelievers. In the models it is averaged over all enthusiasts.
 The Reproduction Potential is the number of people one enthusiast would bring to faith and make an enthusiast, during their entire enthusiastic period, if all the people they contact were unbelievers. In the models it is averaged over all enthusiasts. The reproduction potential must be at least one if enthusiasts are to reproduce themselves. The actual number made enthusiasts drops as church grows, as there are less unconverted people to contact. Growth stops because the actual number of people made enthusiasts drops to a point where enthusiasts do not reproduce themselves.
 Victory Church Cwmbran, Outpouring Day 88, Saturday 6th July, 2013. Available by podcast from Itunes store. See also my blog: A Bad Night for Foxes: A Meeting at the Cwmbran Outpouring.