On his flight to Rome from Baghdad on Monday, Pope Francis said that Iraq's top Shiite cleric is a "humble and wise man," and their March 6 meeting had a "universal message" about the importance of fraternity.

The landmark meeting with Grand Ayatollah Ali al-Sistani took place on the second day of Pope Francis' historic three-day trip to Iraq March 5-8.

During an in-flight press conference on the flight back to Rome March 8, the pope was asked if the meeting with al-Sistani was a message to the religious leaders of Iran.

"I believe it was a universal message," Pope Francis responded. "I felt the duty of this pilgrimage of faith and penance to go and find a great, a wise man, a man of God."

Francis added that these qualities could be perceived only by listening to al-Sistani. "This meeting did my soul good. He is a light," he said. 

The two men spoke for around 45 minutes during a private meeting at al-Sistani's residence in Najaf, central Iraq, according to Matteo Bruni, director of the Holy See press office. Najaf is the third holiest city of Shiite Islam after Mecca and Medina.

The meeting was a milestone in relations between the Catholic Church and Shiite Islam.

Pope Francis described the encounter with al-Sistani as "very respectful," adding that he felt honored that the 90-year-old Shiite cleric rose to greet him twice, a thing he ordinarily does not do.

Describing the religious leader as someone with wisdom and prudence, Francis commented that wise people are everywhere, because "God's wisdom has been spread all over the world."

Pope Francis' in-flight press conference ended a trip of a little over three days in Iraq. He was the first pope to ever visit the Middle Eastern country, where he went to encourage the persecuted Christian minority and to foster interreligious fraternity.

The journey took Francis 900 miles within Iraq, where in addition to his meeting with al-Sistani, he spoke to political leaders and Christian communities.

The pope stayed in Baghdad, and also visited the Plain of Ur, which is the birthplace of Abraham, as well as Najaf, Nassiriya, Erbil, Mosul, and Bakhdida, also known as Qaraqosh.

According to Bruni, in his encounter with al-Sistani, Francis "stressed the importance of cooperation and friendship between religious communities for contributing -- through the cultivation of mutual respect and dialogue -- to the good of Iraq, the region and the entire human family."

Aboard the papal plane, Pope Francis also spoke about his 2019 joint document on human fraternity, which he signed with Ahmed el-Tayeb, Grand Imam of al-Azhar, during an interreligious meeting in Abu Dhabi.

That document, signed on Feb. 4, 2019, "was prepared with the grand imam in secret for six months, praying, reflecting, correcting the text," the pope revealed.

The document was "a first step," he added, noting that afterward he was inspired to write his 2020 encyclical on human fraternity, Fratelli Tutti.

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"The path of fraternity is important," he said. "Both documents must be studied because they go in the same direction, they are seeking fraternity."

Francis recalled a phrase used by al-Sistani: that "men are either brothers by religion or equal by creation."

"And fraternity is equality. I believe it is also a cultural path," the pope added.

According to Francis, the Church's thinking on fraternity has changed, especially with the teaching of the Second Vatican Council.

Pope Francis said that there were critics who accused him of not being courageous, or who said that he had gone against Church doctrine or committed heresy. But he said that criticism was one of the risks of trying to advance interreligious dialogue.

"But these decisions are always made in prayer, in dialogue, asking for advice, in reflection. They are not a whim and they are also the line that the [Second Vatican] Council has taught us," he emphasized.