"Here in Mosul, the tragic consequences of war and hostility are all too evident," he said.
"How cruel it is that this country, the cradle of civilization, should have been afflicted by so barbarous a blow, with ancient places of worship destroyed and many thousands of people -- Muslims, Christians, Yazidis, and others -- forcibly displaced or killed."
"Today, however, we reaffirm our conviction that fraternity is more durable than fratricide, that hope is more powerful than hatred, that peace is more powerful than war. This conviction speaks with greater eloquence than the passing voices of hatred and violence, and it can never be silenced by the blood spilled by those who pervert the name of God to pursue paths of destruction."
Putting on a stole, the pope introduced the prayer of suffrage.
He said: "If God is the God of life -- for so he is -- then it is wrong for us to kill our brothers and sisters in his Name."
"If God is the God of peace -- for so he is -- then it is wrong for us to wage war in his Name."
"If God is the God of love -- for so he is -- then it is wrong for us to hate our brothers and sisters."
He then offered the prayer, which referred to Mosul's Church of Our Lady of the Hour, which has a famous clock tower. The pope said that the clock "for more than a century has reminded passersby that life is short and that time is precious."
"Teach us to realize that you have entrusted to us your plan of love, peace, and reconciliation, and charged us to carry it out in our time, in the brief span of our earthly lives," he prayed.
"Make us recognize that only in this way, by putting it into practice immediately, can this city and this country be rebuilt, and hearts torn by grief be healed."
He continued: "Help us not to pass our time in promoting our selfish concerns, whether as individuals or as groups, but in serving your loving plan. And whenever we go astray, grant that we may heed the voice of true men and women of God and repent in due time, lest we be once more overwhelmed by destruction and death."
After the prayer, the golden cross was unveiled, revealing a centerpiece depicting historical sites in Mosul.
The pope then released a dove, which remained standing in his palm, before flying up into the air.
A commemorative plaque was unveiled in honor of Francis' visit.
It said: "'How beautiful are the feet of messengers of peace' (Romans 10:15). In commemoration of the visit of His Holiness Pope Francis, as a messenger of peace and fraternal love, to the city of Mosul and to the Plain of Nineveh. Here, where Christians endured compulsory displacement (2003-2017), the pope prayed for the spread of peace and justice, serene coexistence and human fraternity."