It's becoming a familiar argument... Christmas has been commercialised beyond all recognition. Easter is going the same way. So the church needs to take them back!

I'm not really convinced. Of course a lot of the meaning of Christmas and Easter has been lost but many of us still in churches still mark the great feasts with joy and celebration.

One idea I do find myself attracted to, though, is celebrating a day that doesn't have any commercial baggage attached. That day is Pentecost. It's one of the most significant dates in both the Eastern and Western church calendars.

Beginning, like many Christian feasts, in the Jewish calendar, the roots of Pentecost are in Shavuot – the commemoration of the giving of the Law to Moses. No doubt the followers of Jesus were gathered together in Jerusalem to commemorate. Little did they realise they were about to go from being just a rag tag band of followers to something else entirely.

In Acts 2 we read, "There came a sound like the rush of a violent wind, and it filled the entire house where they were sitting... All of them were filled with the Holy Spirit and began to speak in other languages, as the Spirit gave them ability."

This was the birth of the Church. The believers had the Holy Spirit poured out on them. Jesus had promised this would happen and after His ascension, and it did. In John 14, Jesus says, "the Advocate, the Holy Spirit, whom the Father will send in my name, will teach you all things and will remind you of everything I have said to you."

So, the power of God had come upon them. It meant a total transformation of everything they had understood. Not only was this a personal transformation for the disciples and the indwelling of the power of God, it had also broken down the barriers among them and between them and the crowds who gathered to watch.

Acts 2 says, "The crowd gathered and was bewildered, because each one heard them speaking in the native language of each. Amazed and astonished, they asked, "Are not all these who are speaking Galileans? And how is it that we hear, each of us, in our own native language? Parthians, Medes, Elamites, and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabs--in our own languages we hear them speaking about God's deeds of power."

In other words, God had delivered on His promise to use Israel to reach the whole world. The Jewish Messiah was being proclaimed by His Jewish followers. Suddenly, miraculously, gentiles were able to understand. They began to hear of the life, death and resurrection of Jesus and they began to believe.

Others were more sceptical. They suspected the disciples were drunk. Not so, said Peter and went on to quote from the book of Joel, "In the last days it will be, God declares, that I will pour out my Spirit upon all flesh, and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams."

We learn that thousands were added to that number on that day and since then, the day of Pentecost has been remembered as the birth of the Church.

What can this tell us today? Commemorations of Pentecost are almost nonexistent in secular society. Parts of South America see joyous celebrations, but in Europe and north America, it isn't really a big deal. The exception is in my native North West of England, where Whit Walks (the English term Whitsuntide was used for Pentecost) are still prevalent.

The message of Pentecost reaches far beyond a walk though. It speaks to the very nature of the Church. From its foundation, the Church has been radically diverse. The Jerusalem of the first century was a fairly cosmopolitan place as the passage from Acts implies – there were people from all across the known world there.

The disciples had seen Jesus reach out across ethnic and religious divides birth in His parables and in real life. The hated Samaritans and the occupying Romans were both shown to be within the reach of the grace of God. Yet until the spirit was poured out at Pentecost, the disciples were a homogenous bunch. They were Jewish, and they were Galileans at that. But from the day of Pentecost onwards, all that was set to change. The birth of the Church, the very first day of its existence, saw people of many languages and cultures brought together to worship.

It is a foretaste of the passage in Revelation where, "A great multitude that no one could number, from every nation, from all tribes and peoples and languages, standing before the throne and before the Lamb."

In our current age of migration crises, anxiety about radical Islam, debates over building walls between countries and whether other countries should break apart or leave unions, the day of Pentecost speaks to us afresh.

Theologian Esther D Reed describes Pentecost as an "inherently political" activity. She says, "It was the speaking of the truth of the Gospel into a public place. When that happens, that's political. Christian people shouldn't be afraid of the political – we need to speak truth into the political context and then events happen. Pentecost was an event. It was an opening of that present moment to the power of God's truth and it was prophetic."

Pentecost tells us that though ethnicity, culture, language and place are all important parts of us and our people, they can never Trump (so to speak) our status as sisters and brothers in Christ. Since its foundation, the Church has been a diverse alliance of people from across the world. And despite many ugly scenes since, at its best, that is what the Church remains.

Putting this into practice is difficult. Martin Luther King's sad observation that Sunday Morning is the most segregated time of the week still remains true. But the day of Pentecost tells us it wasn't always that way, it doesn't have to be that way now and it won't be that way in the fullness of the Kingdom.