Pope Francis said on Wednesday he is going to Iraq, where his predecessor John Paul was not allowed to go in 2000, because "the people cannot be let down for a second time."
Speaking at the end of his general audience, Francis, who is due to start the risky trip in Baghdad on Friday, asked for prayers so that the visit "can take place in the best possible way and bring about the desired fruits".
He made no mention of the deteriorating security situation in Iraq, where earlier on Wednesday at least 10 rockets landed on an air base that hosts United States, coalition and Iraqi forces.
Pope John Paul had to cancel a planned trip in 2000 after a breakdown in talks with the government of then leader Saddam Hussein.
"For some time I have wanted to meet that people who suffered so much, and meet that martyred Church," Francis said.
Iraq's minority Christian community has been devastated by wars and repression by Islamic State insurgents. Francis will visit the former Islamic State stronghold of Mosul, where churches still bear the signs of conflict.
"The people of Iraq are waiting for us. They were waiting for St. Pope John Paul II, who was not allowed to go. The people cannot be let down for a second time. Let us pray that this trip can be carried out well," he said.
Francis will also visit Ur, birthplace of the prophet Abraham, who is revered by Christians, Moslems and Jews, and meet Iraq's top Shi'ite Muslim cleric, Grand Ayatollah Ali al-Sistani, 90.
"In the land of Abraham, together with other religious leaders, we also will take another step forward in fraternity among believers," Francis said.
Al-Sistani is one of the most important figures in Shi'ite Islam, both within Iraq and beyond. He commands a vast following among Iraq's Shi'ite majority and huge influence over politics and public opinion.
About 10,000 security forces will be deployed to protect the pope, who will mostly likely be travelling in armoured vehicles.
The number of people who will be able to see him has been severely limited because of coronavirus restrictions.