THERE was no simple, single message in yesterday's service in Glasgow Cathedral to mark the centenary of the First World War, no explanations, no defining summary of what war really means.

The cathedral's minister Rev Dr Laurence Whitley told the congregation that no such summary exists, only a responsibility to remember, reflect and learn.

The congregation that came to reflect included guests from across the Commonwealth including the Duke of Rothesay, the Prime Minister David Cameron, First Minister Alex Salmond and other political leaders. The aisle was also lined with veterans of conflict, some frail and in wheelchairs, others ramrod straight.

The story they heard was of the courage of the men who fought in the war, and their families, told through extracts from the diaries and letters of the dead. One of the most moving was the account of Captain Ronald Rose of the 1st Cameronians who described the battlefield as a little corner of hell. He was killed a few weeks later.

Joanne Thomson, a drama student from Glasgow, also read an account by Helen Thomas, the wife of the poet Edward Thomas, of the last day they spent together before he returned to the front. "I stood at the gate watching him go," she wrote, "then, with leaden feet, I groped my way back to the empty house."

It was these accounts, spread throughout the service, which wielded the most power, although the scale of the deaths among the men of the Commonwealth was also revealed. The broadcaster Sir Trevor McDonald listed the grim numbers: 59,000 Australians, 66,000 Canadians, 54,000 Indians dead, and on and on. Ranjan Mathai, High Commissioner for India, read the words of Sowar Sohan Singh, who served with the 9th Hodson's Horse. "Here thousands of lives have been sacrificed," he said. "Scratch the ground to the depth of one finger and nothing but corpses will be visible."

Sir Trevor also reminded the congregation of the scale of the British losses and in particular the Pals battalions, groups of friends and colleagues who signed up together. Among them were the Glaswegians who volunteered for the Highland Light Infantry from the city's tramways and the Boys Brigade.

There was then a minute's silence before the congregation left through the Great West Door, each carrying a poppy, red spots against black. Rev Dr Whitley called on everyone to leave their poppy in a place they thought appropriate and one member of the congregation, Daniel Macrae, knew exactly where he would leave his. Later, he said, he would place it on the grave of his nephew, 20-year-old Private Thomas Haggerty, from Glasgow, who was killed in the Gulf War in 1991.

The dignitaries then moved on to George Square, where they laid wreaths at the cenotaph and started something of a row over the messages written on them. Mr Cameron's was personal while Ed Miliband's said only "From the leader of the opposition". It later emerged the Labour leader had not been given an opportunity to write a personal message.

Back at the cathedral, the rest of the congregation did what they had been instructed to do: remember, reflect and learn. General Sir Peter Wall, chief of the General Staff, said yesterday that the military had learned from its decade-long operation in Afghanistan and now had a "warrior generation" of troops ready for future conflicts, but that's probably not the kind of learning that was needed yesterday. Perhaps one of the prayers in the cathedral put it best: "may the example of those who have gone before us bring us ever closer together".