How we live out our faith in society has always been a central question for Christians.

When we show people what it looks like to embrace the gospel in every area of our lives – or in reality, to fail to but try our best – then we show people who Jesus is. We start to become his faithful witnesses.

In writing Reimagining Britain, I've tried to make a personal contribution to the challenge I believe lies before us: reimagining our future at this critical time in the life of our country. It's my belief that the values we find in our Christian heritage – compassion, generosity, and solidarity to name a few – offer a source of hope and wisdom for Britain in the 21st century, even as we rightly embrace who we are becoming as a multi-faith and multi-cultural society.

The book asks fundamental questions about the kind of society we want to be in 10 to 20 years' time. These are everyday questions that matter to ordinary people across our parishes in the Church of England – on education, health, housing, the family, the economy, the world around us, the environment and more. It's about how we might identify and develop the values to help us reimagine a more hopeful future – drawing on the Bible, Britain's history and its Christian tradition.

It begins with a look at the reasons why reimagining is so important. There are certain key areas where our values are translated into action and virtues, including the big three of recent history: health (especially public and mental health, and social care), housing and education.

On top of these are family; the environment; economics and finance; peacebuilding and international development, and finally immigration and integration. Perhaps not surprisingly, I'm particularly interested in how the church and faith groups can contribute to a fairer, more hopeful future.

It's not a complete list, and it certainly doesn't try to set out any kind of political programme. Instead it's a contribution – from a distinctly Christian perspective – to the widespread, urgent and exciting debates happening all around us.

Archbishop William Temple lamented in 1942 that 'few people read much history nowadays'. For Temple the commonly held assumption that religion and politics had no connection to each other was historically illiterate. It was a very modern heresy. But since 1942 that loss of historical depth has deeply affected our public life. The role of religion in shaping public policy and informing the moral shape of our nation has been similarly forgotten.

One of the biggest differences between Temple's time and ours is that fewer people in our population generally are aware of what religion (and specifically Christianity) is all about.

As we become less capable of thinking about religion, or any transcendent idea like 'God', we hear the question more and more: what right does the church have to interfere in society?

As I've said, what it looks like to be a faithful follower of Jesus Christ in everyday life on this earth is one of the central questions for Christians.

In the Old Testament, we read in Jeremiah 29:7 of God's call to his people in exile: 'But seek the welfare of the city where I have sent you into exile, and pray to the Lord on its behalf, for in its welfare you will find your welfare.'

While aliens and strangers in this world, we still seek its welfare.

And here's the bigger context of all this: 'The earth is the Lord's and all that is in it, the world, and those who live in it' (Psalm 24:1). It all belongs to God, and the Bible details the kind of relationships – one to another, to the oppressed, to the marginalised, to creation – that he desires.

In the words of Micah: 'He has told you, O mortal, what is good; and what does the Lord require of you but to do justice, and to love kindness, and to walk humbly with your God?'

Being a follower of Jesus Christ has always profoundly challenged us in how we treat other people – and how we live as individuals, families and societies. We are not 'otherworldly'. Disengaging from the world is not an option because of who God is.

God is the one who continually engages with his world.

God is the one who cries out for the rights of the poor and oppressed.

God is the one who offers salvation, creates a new people called the church and calls that church to share in building his Kingdom.

That's why how we reflect on human life matters.

I hope my reflections on these issues will be of some benefit as we navigate these choppy waters. Ultimately as Christians we look to God as ruler of the nations. We continue to pray for everyone – including those who lead our countries – 'so that we may lead a quiet and peaceable life in all godliness and dignity. This is right and is acceptable in the sight of God our Saviour, who desires everyone to be saved and to come to the knowledge of the truth' (1 Timothy 2: 1-4).

Justin Welby is the archbishop of Canterbury. His book 'Reimagining Britain' (Bloomsbury) is out now.