Have you ever noticed that laughter is contagious?

The video is actually a social experiment. With hidden cameras set up at a local bus stop, an actor is sent in among the “regular” folks. As you can see, at a certain point, the actor begins laughing, first to himself and then more heartily. Eventually, even the most hesitant among the group begins to smile and take part in the communal laughter — because laughter is contagious.

According to Sophie Scott, a neuroscientist at University College London, laughter is contagious because our brains perceive laughter as something positive. In her research, Scott and her team played a series of sounds to volunteers and measured the responses in their brains with an fMRI scanner. Some sounds were positive, like laughter or a baby cooing or triumphant shouts, while others were negative, like screaming or retching.

All of these sounds trigger responses in the region of the brain that prepares your face muscles to move in a way that corresponds to the sound. But they found that response was much higher for positive sounds, suggesting they are more contagious than negative sounds – which could explain our involuntary smiles when we see people laughing. That’s why the laugh track was invented.

It seems that something good and positive is more contagious than anything else.

Perhaps this explains the story of the early church. In the book of Acts, the church bursts onto the scene with a flourish, a force for good unlike anything the world has ever seen. And the church experiences incredible growth from the outset. And as we’ll see by looking at Acts 2, this growth is attributed to these earliest Christians being devoted to a good and positive way of life — a missional way of life.

They devoted themselves to the apostles’ teaching and to the fellowship, to the breaking of bread and to prayer. Everyone was filled with awe, and many wonders and miraculous signs were done by the apostles. All the believers were together and had everything in common. Selling their possessions and goods, they gave to anyone as he had need. Every day they continued to meet together in the temple courts. They broke bread in their homes and ate together with glad and sincere hearts, praising God and enjoying the favor of all the people. And the Lord added to their number daily those who were being saved.

This summary statement comes on the heels of Peter’s sermon on the Day of Pentecost. After Peter declares the Good News, about 3,000 people received the word and were baptized. This act of repentance signals the beginning of a new way of life. These 3,000 people didn’t “join” the church; they were added by God Himself. In the New Testament, you don’t “join” a church; you become the church.

And Luke describes the way of life of these earliest Christians. He says in v42 that they were devoted to a particular way of life. The word “devoted” means “to be diligently preoccupied, to hold fast.” The believers are sold out to the way of life that Luke describes.

Luke identifies four areas of common devotion among God’s people:

• The apostle’s teaching – the story of Jesus as the ultimate fulfillment / focal point of the biblical narrative.
• Fellowship – koinonia, a shared life together. We share Jesus in common, that means we share life together.
• Breaking of bread – communion together. This practice is a demonstration of our fellowship with one another.
• Prayer – the early church was steadfast in her prayer life.

Moving from these practices, Luke spells out some of the church’s core values:

• Awe (v43) – everyone was filled with awe at the many wonders taking place in their midst. God was regularly at work among His people, prompting the believers to recognize that “our God is an awesome God.”
• Friendship (v44) – all the people were together and had everything in common. This line is an allusion to a well-known Greek proverb concerning friendship: “friends hold all things in common.” Greek philosophers cited this proverb as a feature of their utopian visions of society. The best societies were envisioned as networks of friendship. With this phrase, Luke vividly describes the church as a place of deep, true friendship.
• Generosity (v45) – believers sold their possessions and gave to meet the needs of others. Luke says they gave indiscriminately, helping anyone in need. Love for others was manifest through generosity and compassion.
• Table Hospitality (v46) – they broke bread regularly. The table is one of the central icons in the Christian faith and we see the power of the table here. Sharing a meal together is still one of our most formative practices.
• Joy (v46) – they lived with glad and sincere hearts. To be glad is to be joyful. The early Christians were a people of celebration. They were Good News people. The irony here is that they took their salvation seriously — which prompted them to be incredibly joyful!
• Worship (v47) – they continue to praise God, in particular through song. Their love for God was evident by the way they worshipped together.
• Community (v47) – they enjoyed the favor of the community. “Favor” is literally “grace.” In context, it means good will. The surrounding community understood this way of life as something good and positive.

The favor they enjoyed in the community helps to explain the final line of the text: And the Lord added to their number daily those who were being saved. This new entity that comes to be known as “the church” was immediately perceived as something good and positive. Like laughter spreading through a bus stop, this Gospel-formed way of life was contagious.

And another word we could use to describe this way of life: missional.

The word “missional” is not a description of a specific activity of the church or one of the many programs of the church. Instead, “missional” gets at the very essence and identity of the church. “Missional” is not something we do, it’s who we are. Remember, the earliest Christians didn’t join a church; they became THE church. And by becoming the church, they embraced this way of life that the world perceived to be good. People in the community benefitted from the church’s existence. And that created missional opportunities for God’s people.

To be “missional” is to live “on mission.” And what is our mission? Love is our mission. As I’ve been writing for several months now, love prompted God to send Jesus into the world on a mission of redemption (John 3:16). And Jesus leaves His followers a mission to make disciples through sharing the Good News (Matt. 28; Acts 1:8). But Jesus grounds all of this in love when He teaches His followers that the greatest commands are to love God and love others. The believers we read about in Acts 2 were devoted to loving God and loving others. And by living “on mission” — living in obedience to the greatest commands of Jesus — their lives had a “missional” quality. By loving God and loving others, their numbers grew.

It has been said that the church is the only society that exists for the benefit of those who are not its members. Like Abraham in Genesis 12, the church understands her blessings as opportunities to bless others. We’ve been blessed in order to be a blessing. This is the missional perspective: our lives announce the Good News by showing the world what it looks like to love God and love others.

The early church didn’t grow because they were recruiting members to the cause. People don’t want to be recruited. People want to be loved. We want to experience love and to see love modeled. And there was something about those earliest believers — something about the way they loved — that was certainly contagious.

We might call it a missional way of life.