Pope Francis has condemned the drug trade's "dealers of death" and urged Mexicans to shun the devil's lust for money as he led a huge open-air mass for more than 300,000 people.
"Let us get it into our heads: With the devil, there is no dialogue," the Pope said at the biggest scheduled event of his five-day visit to Mexico.
Francis brought a message of encouragement on the second full day of his trip to residents of Ecatepec, a poverty-stricken Mexico City suburb of some 1.6 million people where drug violence, kidnappings and gangland-style killings, particularly of women, are a fact of life.
In a clear reference to the drug lords who hold sway in the city's sprawling expanses of cinderblock slums, the Pope focused his homily on the danger posed by the devil.
"Only the power of the word of God can defeat him," he said.
In a final prayer, he urged Mexicans to make their country into a land of opportunity "where there will be no need to emigrate in order to dream, no need to be exploited in order to work, no need to make the despair and poverty of many the opportunism of a few, a land that will not have to mourn men and women, young people and children who are destroyed at the hands of the dealers of death."
The faithful lined the Pope's motorcade route to the huge field where the mass took place, tossing flower petals as he passed by and cheering with pom-poms in the yellow and white of the Vatican flag.
The Pope's gruelling schedule seemed to take a toll on him on Saturday, when the 79-year-old pontiff appeared to nod off at an evening Mass and also lost his balance and fell into a chair set up for him.
He appeared much livelier on Sunday, beaming and waving at the crowds along his route.