By Kevin Kim BBC News, Seoul

The South Korean Christians were doing voluntary work in Afghanistan

When South Korean TV broadcast news that hostages held by the Taleban were to be released, cheers of joy echoed through the church where the families of the Christian aid workers had been waiting for more than a month.

As South Koreans went to work on Wednesday morning, they could not escape the news of the deal struck to free 12 of the 19 hostages.

The government expects the remaining seven hostages to be freed in the coming days.

The headline of one newspaper said that a 40-day nightmare was finally over, and a collective sense of anxiety finally turned into a sense of relief.

But what lessons have been learned from the ordeal?

New approach

Even as vigils were held to pray for the safe return of the hostages, many difficult questions were also asked about Christian missionaries ignoring official warnings about threats to their safety.

I think we really have to refrain from going to countries where the government says it's too dangerous Baek Joo Han, student

"I have been on Christian aid missions myself," said Baek Joo-han, a 22-year-old university student in Seoul.

"Other countries may see us as dogmatic and being too selfish, but we are going to other countries to help people out of pure love. We shouldn't be doing things that are bad for our country, though.

"I think we really have to refrain from going to countries where the government says it's too dangerous," he said.

Some 25% of the South Korean population is Christian, about 15,000 of whom work as missionaries overseas.

But some Christian leaders believe South Korea now has to re-assess some of its missionary work in culturally sensitive areas.

HOSTAGE TIMELINE 19 July: 23 South Korean Christian aid workers seized on bus in Ghazni province 26 July: Body of hostage Pastor Bae Hyung-kyu is found 31 July: Second hostage Shim Sung-min, 29, found shot dead 13 August: Two hostages freed 29 August: 12 of remaining 19 hostages released

Dr Steve Moon, the director at the Korea Research Institute for Mission, says the hostage incident will help South Korean missionaries become more mature.

"South Korean missionaries have been fairly free up to now to spread the gospel in areas where Western evangelicals have difficulty accessing.

"But now there are greater risks of identities of the South Korean missionaries becoming exposed. There will need to be greater transparency," Dr Moon says.

But it is not entirely a happy ending.