On April 9 1945; just days before the US army would liberate Flossenburg prison where he was being held, Dietrich Bonhoeffer was hanged. Bonhoeffer had lead the Confessing Church in Nazi Germany and was just 39 when he died.

Bonhoeffer was outspoken in his opposition to the Nazis and was willing to speak out not just about Hitler's dictatorship but also his euthanasia programme and the Jewish holocaust. Bonhoeffer had many opportunities to escape Germany; yet deliberately chose to continue his work serving the Confessing Church, a group of churches that refused to allow their pulpits to be used for Nazi propaganda. In 1943, just after getting engaged, Bonhoeffer was arrested and taken to Tegel prison and then later to Flossenburg where he was exectuted.

Bonhoeffer was a pastor, theologian and poet. His theology fuelled his political engagement and it cost him his life. Through his writings he remains a powerful prophetic voice to the church. Alongside CS Lewis he is one of the world's most quoted theologians; his personal courage and martyrdom bring authenticity to his challenging words. 70 years on from his death, it is vital that his call to costly and courageous discipleship is still heeded. Here are 10 quotes which still speak truth today.

1. On hardship...

"You have granted me many blessings; let me also accept what is hard from your hand." (Prayers for Fellow Prisoners, Christmas 1943)

2. On challenging injustice...

"We are not to simply bandage the wounds of victims beneath the wheels of injustice, we are to drive a spoke into the wheel itself."

3. On pastoring...

"A pastor should never complain about his congregation, certainly never to other people, but also not to God. A congregation has not been entrusted to him in order that he should become its accuser before God and men." (Life Together)

4. On materialism...

Earthly possessions dazzle our eyes and delude us into thinking that they can provide security and freedom from anxiety. Yet all the time they are the very source of anxiety. (The Cost of Discipleship)

5. On peace...

"There is no way to peace along the way of safety. For peace must be dared, it is itself the great venture and can never be safe. Peace is the opposite of security. To demand guarantees is to want to protect oneself. Peace means giving oneself completely to God's commandment, wanting no security, but in faith and obedience laying the destiny of the nations in the hand of Almighty God, not trying to direct it for selfish purposes." (Meditations on the Cross)

6. On cheap grace...

"Cheap grace is the grace we bestow on ourselves. Cheap grace is the preaching of forgiveness without requiring repentance, baptism without church discipline, Communion without confession...Cheap grace is grace without discipleship, grace without the cross, grace without Jesus Christ, living and incarnate." (The Cost of Discipleship)

7. On self-importance...

"In normal life we hardly realize how much more we receive than we give, and life cannot be rich without such gratitude. It is so easy to overestimate the importance of our own achievements compared with what we owe to the help of others."
(Letters and Papers from Prison)

8. On worth...

"Christianity preaches the infinite worth of that which is seemingly worthless and the infinite worthlessness of that which is seemingly so valued."

9. On fellowship...

"A Christian fellowship lives and exists by the intercession of its members for one another, or it collapses. I can no longer condemn or hate a brother for whom I pray, no matter how much trouble he causes me. His face, that hitherto may have been strange and intolerable to me, is transformed in intercession into the countenance of a brother for whom Christ died, the face of a forgiven sinner." (Life Together)

10. On Christ...

"Christianity without the living Christ is inevitably Christianity without discipleship, and Christianity without discipleship is always Christianity without Christ." (The Cost of Discipleship)

Dr Krish Kandiah is a contributing editor to Christian Today. He is President of London school of Theology and the Founder of the fostering and adoption charity Home for Good.