Proper 17: Jeremiah 15.15-2; Romans 12.9-end; Matthew 16.21-end

O God, you declare your almighty power most chiefly in showing mercy and pity: mercifully grant to us such a measure of your grace, that we, running the way of your commandments, may receive your gracious promises, and be made partakers of your heavenly treasure; through Jesus Christ our Lord. Amen.

"DO NOT be overcome by evil, but overcome evil with good."

In July, in the build-up to the beginning of the four-year commemoration of the First World War, we held a study morning at Durham Cathedral on Hensley Henson, the Dean of Durham during that war. His copious journals, letters, and sermons shed light on how he tried to respond faithfully to the shock of his world's being plunged into conflict.

Always aware of his pastoral responsibilities to the troops who hastily assembled, and to the people of Durham who were being asked to send their men to war, inevitably he worked with the themes in this week's readings. So, preaching in the first days of the war, Henson drew parallels between Jerusalem, invaded by Antiochus Epiphanes, and the Belgian people, who did not deserve the cruel treatment that they had received from the Kaiser and his army.

A few weeks ago, Jeremiah was berating God for enticing him, and now God has deceived him. He had been utterly faithful, had truly delighted in God's word, and was glad to be called by God's name. So it was reasonable to ask why his pain was unceasing and his wound was incurable, like a running sore that would not heal.

He was extraordinarily bold, given God's impatience with grumblers. Yet, because Jeremiah's heart was set on God, his was a lament, not a whinge; and God took him utterly seriously, responding with profound promises.

Jeremiah's situation leaps across the centuries. People still struggle to be staunch in their commitment to God through dreadful situations, and many Christians are supporting people through unfair and unrelieved suffering. Paul's exhortation was directed at a Church that, in its short life, had already faced cruel persecution, martyrdoms, and, for its Jewish members, exile.

"Be patient in suffering, do not lag in zeal, be ardent in spirit," were gritty and tall orders for his readers, given what the Romans had endured. Paul went on relentlessly with demanding words that describe Jesus Christ's example to us: "Do not repay anyone evil for evil. . . If it is possible, so far as it depends on you, live peaceably with one another. . . Do not be overcome by evil, but overcome evil with good."

It is worth noting that Paul said "if it is possible, so far as it depends on you": sometimes, it is not possible, and does not completely depend on us. Then, like Henson, we face hard decisions about how to respond to evil.

From the start of his wartime preaching, Henson was resolute that there should be no animosity against the German people, whom he saw as hoodwinked by their leaders. So, preaching on "salt and light" in July 1915, he described as anti-Christian the inevitable demand for reprisals and vengeance which would arise as the war continued, and fresh provocations provoked exasperation.

The test of the English Church, revealing whether salt had lost its savour or light had been darkened, would come when, ultimately, the German nation learned how its leaders had wronged it. For his congregation in Sunderland, after a year of "unprecedented slaughter and devastation", those were prophetically uncomfortable words, which echo Jeremiah's entrusting of his yearning for retribution to God.

As we begin to commemorate the Great War, and as we hear the dreadful news reports of the continuing slaughter of innocent people today, of revenge killings of more innocent people, of there being more refugees now than at any time since the Second World War, these readings confront us.

Few of us face such absolutely desperate situations, but we do encounter situations in which it is hard to rejoice in hope, be patient in suffering, and persevere in prayer. Jeremiah's brutally honest response was to plead to be remembered by God, and to hand over his instinctive desire for vengeance to God for action rather than take it himself.

Paul made extraordinary demands of his readers, given their circumstances: contributing to the needs of the saints was one thing, but feeding their merciless enemies was another. Radically counter-cultural, it could spring only from an attitude that "take[s] thought for what is noble in the sight of all".

While Peter wanted Jesus to bypass suffering, Jesus held his life in a different perspective, and faced suffering head-on. Paul's final words sum it up: "Do not be overcome by evil, but overcome evil with good."