Western society struggles with forgiveness. Whether it's Black Lives Matter, the #Metoo movement or other victims of discrimination and abuse, it's deeply controversial when people suggest that the perpetrator might merit any kind of forgiveness.

Quite rightly, many would say. It's the victims that need our compassion and concern. Those committing the offences deserve nothing less than judgement and punishment.

But where does Jesus's command to "forgive other people when they sin against you" (Matthew 6:14) and Christ's teaching around forgiving others as a sign of our faithful discipleship, come into this?

Where does the Lord's Prayer, when we pray "forgive us our sins as we forgive those who sin against us," fit into this landscape?

Is Christ's teaching on forgiveness really suited for our 21st century world and its widespread 'blame culture'?

These are just some of the topical, urgent questions confronted by American pastor and author Timothy Keller in his latest book, 'Forgive' published this month. Subtitled 'Why should I and how can I?', Keller sets out to explain how Jesus showed his followers how to live with a spirit of forgiveness and how that could apply in today's world.

A key element of Keller's argument is that forgiveness does not rule out justice. Christians serve a God who hates injustice and numerous Bible verses speak out strongly against oppression.

Keller writes "Christian forgiveness is never simply individualistic – concerned only with inner healing of the heart. It is at least that, but it is much more. God's concern is for the outer and social healing of the community as well."

He emphasises that "Christian forgiveness never undermines the pursuit of justice but promotes it. Because injustice grieves the God we love, it mars the creation we love, it harms people we love, and it even harms the wrongdoer, whom we should love and not hate."

What is seeking justice, Keller asks? He responds, "It is to speak the truth in love and to not shield people from the consequences of their actions," and adds, "To be morally outraged out of love for God, his creation, people and even the offender is rare – but required."

In a wide-ranging examination of forgiveness, Keller looks at the writings of Hannah Arendt, a Jewish political philosopher writing after the Holocaust, American civil rights leader Martin Luther King Jr, and South African bishop and anti-apartheid campaigner Desmond Tutu.

Keller writes, "We have ringing insistent calls to forgive from all three people representing groups who were egregiously oppressed in the twentieth century." They "represent times in history in which horrendous, systemic oppression had to be met with both truth and love, both justice and forgiveness."

But, Keller adds, "These 'big forgivenesses' should not obscure our urgent need for learning how to do small 'forgivenesses' every day. We can't love without forgiveness, but we can't live without it either."

Keller's examination of forgiveness begins with the Matthew 18 parable of the Unforgiving Servant and sets out to show how "forgiveness is at the heart of the Christian message and all throughout the Bible."

In a set of 'forgiveness principles,' Keller writes that forgiveness is "unnatural, not the nature of things", that its dynamic comes from the atoning death of Christ on the Cross and that the 'fading' of forgiveness in contemporary society has arisen because current therapeutic models do not take God into account.

Christian forgiveness, he says, seeks both justice and reconciliation. It offers internal forgiveness and has both costliness and power.

'Forgive' will make challenging reading for anyone who believes that forgiveness should never be given - or that people should always forgive, without seeking justice. Keller sets out a strong Biblical case for forgiveness but does not ignore its cost to the individual or to groups of people.

At a time when we are understanding more about situations where the Church has forgiven or excused perpetrators in our midst without justice, and when church authorities are beginning to listen more carefully to the voices of victims, Keller's book is timely.

In a poignant acknowledgement at the end of 'Forgive,' Keller – who is currently receiving treatment for pancreatic cancer – comments, "Covid and cancer treatments have changed my life in many ways, yet, as always, God works things for good."

He writes of being able to spend more time with his wife, Kathy, and having "co-learned the meaning and practice of forgiveness together over the decades."

Rev Peter Crumpler is a Church of England minister in St Albans, Herts, UK, and the author of 'Responding to Post-truth.'