A good analysis from Christopher Lamb in The Tablet in the U.K.:
Pope Francis’ historic meeting with Grand Ayatollah al-Sistani marks a new step in Christian-Muslim relations. This is a moment that ranks alongside St John Paul II’s first official papal visits to a synagogue in 1986 and mosque in 2001.
The foundation stone for these groundbreaking moves is the Second Vatican Council’s declaration, Nostra Aetate, which unequivocally condemned anti-semitism, and opened a dialogue with Islam. It transformed the Catholic Church’s relations with other faiths.
That relationship was on display on the morning of 6 March 2021 in the Iraqi city of Najaf. Along the narrow and column-lined Rasool Street, a convoy carrying the Roman Pontiff stopped and the Pope made his way on foot to the modest house rented by al-Sistani, the most revered leader in Shia Islam. The sight of Francis walking to meet the Grand Ayatollah down a narrow alleyway in Najaf is itself a sign. Here was a Pope searching out a fellow leader, and brother. It symbolised the Church’s approach since Vatican II of being willing to “cross over the road” and encounter other religions.
The most obvious impact of this meeting is the new dialogue between the Church and Shia Islam that could now be opening up. Najaf is the Shia equivalent of Rome and the site of “founding father” Imam Ali’s tomb. Even getting the meeting to take place is a major development in Church-Shia relations, because Al-Sistani is a reclusive figure who rarely meets foreign dignitaries. So far most of Francis’ efforts at building bridges with the Muslim world have been with Sunni leaders or Sunni-majority countries.
Al-Sistani is not just a religious leader, but the most influential figure in post-invasion Iraq. He is a peacemaker, who has repeatedly called for calm when the Shi’ite community were being attacked by Sunni extremists. In 2014 he helped boost the numbers of Iraq’s security forces to battle Islamic State and two years ago a sermon he gave led to the resignation of then-prime minister Adil Abdul-Mahdi.
The images of Francis with al-Sistani send a powerful message against extremism. Their encounter shows that true religion is in service of peace and is both a refutation of and deterrent to, those who claim religious support for acts of terrorism or violence.
You can read more about al-Sistani from my colleague Fr. Elias Mallon at CNEWA, who notes:
Though born in Iran, al-Sistani has lived and taught in the Shiite holy city and theological center of Najaf in Iraq for most of his life. He can read the signs of the times and has his own website in several languages; he answers questions posed by the Shiite faithful and makes theological decisions. As a result, he is highly regarded by Shiites far beyond the confines of Iraq.
In a meeting with members of a U.N. fact-finding mission on ISIS atrocities, al-Sistani denounced the “heinous crimes against some members of Iraqi society,” such as the Yazidis in Sanjar and the Christians in Mosul.
For his entire career, al-Sistani has been a voice of reason and moderation and has been an example of the best of the Shiite intellectual and theological tradition.
It’s also interesting to note that, like Pope Francis, he’s been nominated for the Nobel Peace Prize — twice, in fact.