When they offer you the job in Thailand, you can't believe your luck. Moving from your home in Myanmar is a risk, but the wages they are offering will let you and your whole family start a new life. It's almost too good to be true.

In fact, it is too good to be true.

Once you and your family arrive in Thailand, your passports are taken. The work you were promised is a lie, and now the men who brought you here demand that you repay them the cost of your transport and travel documents. You and your sons are trapped on fishing boats, working long hours, enduring beatings and abuse – never seeming to make a dent in your debt.

Back on land, your daughters are sent into the houses of strangers, forced to work as domestic maids. They are subjected to violence and threated with death at the hands of the men who are now controlling you.

These men even sell one of your daughters into marriage with a man she's never met.

Take a moment to imagine it. This is the true story of a Burmese family trafficked into Thailand this year. It is one of thousands and thousands of similar stories. Even right now, people – full of hope for a better future – are travelling into a nightmare without realizing it.

This Sunday, over 5,000 churches in 48 different countries will gather in the hope of giving these stories a different ending.

They are all celebrating Freedom Sunday – a chance to partner with International Justice Mission (IJM), the world's largest anti-trafficking organization, to join the fight against slavery.

Freedom Sunday offers the opportunity to learn about this global scourge, and to do something to end it. 40 million people are trapped in slavery today. That's more people than everyone trafficked in the 200 years of the transatlantic slave trade, combined.

The abolition of that slave trade would not have been possible if Christians had not determined to fight the evil in their time. The Church played a crucial part in bringing radical change to a dark world.

Today, the need for abolitionists is greater than ever. The world cannot afford for the Church to do nothing. God has not forgotten a single one of those 40 million still suffering; the question is – will we?

For that Burmese family trafficked to Thailand, rescue made all the difference. Rescue made possible by people like you. IJM operatives worked with Thai police to piece together their story – and then went with them on rescue operations, freeing and reuniting each member of the family. Their traffickers were arrested and are facing prosecution, and the family is safe and together again at last.

This Freedom Sunday, those 5,000 churches coming alongside IJM will – through their voice, their prayers, and their generosity – send freedom to thousands of other families. It is the beginning of a movement bringing God's heart of compassion and justice to the darkest corners of the world.

If you would like to celebrate Freedom Sunday in your church and send rescue to more families, you can. There's still time. Find more information and resources here.

David Westlake is chief executive of IJM UK.