The Pope has issued his strongest defence yet of church teaching opposing artificial contraception, using a rally in Asia's largest Catholic nation to urge families to be "sanctuaries of respect for life".
Francis also denounced the corruption that has plagued the Philippines for decades and urged officials to work to end its "scandalous" poverty and social inequalities during his first full day in Manila, where he received a rock star's welcome at every turn.
Security was tighter than it has ever been for this Pope, who relishes plunging into crowds. Mobile phone service around the city was intentionally jammed for a second day on orders of the National Telecommunications Commission and roadblocks along Francis's motorcade route snarled traffic for miles.
Police vans followed his motorcade while officers formed human chains in front of barricades to hold back the tens of thousands of cheering Filipinos who packed boulevards for hours for a glimpse of his four-door Volkswagen passing by.
Officers said another 86,000 gathered outside one of Manila's biggest sports arenas, capacity 20,000, where Francis held his first encounter with the Filipino masses: a meeting with families. There, he firmly upheld church teaching opposing artificial contraception and endeared himself to the crowd with off-the-cuff jokes and even a well-intentioned attempt at sign-language.
Francis has largely shied away from emphasising church teaching on hot-button issues, saying the previous two popes made the teaching well-known and that he wants to focus on making the church a place of welcome, not rules.
But his comments were clearly a nod to the local church, which recently lost a significant fight when President Benigno Aquino III pushed through a reproductive health law that allows the government to provide artificial birth control to the poor.
"Be sanctuaries of respect for life, proclaiming the sacredness of every human life from conception to natural death," Francis exhorted the crowd. "What a gift this would be to society if every Christian family lived fully its noble vocation."
He deviated from his prepared remarks to praise Pope Paul VI for having "courageously" resisted calls for an opening in church teaching on sexuality in the 1960s. Paul penned the 1968 encyclical Humanae Vitae, which enshrined the church's opposition to artificial birth control.
Francis noted that Paul was aware that some families would find it difficult to uphold the teaching and "he asked confessors to be particularly compassionate and understanding for particular cases".
But he nevertheless said Paul was prescient in resisting the trends of the times.
"He looked beyond. He looked to the peoples of the Earth and saw the destruction of the family because of the lack of children," Francis said. "Paul VI was courageous. He was a good pastor. He warned his sheep about the wolves that were approaching, and from the heavens he blesses us today."
Francis also urged families to be on guard against what he called "ideological colonisation", an apparent reference to gay marriage, which is not legal in the Philippines. The church opposes gay marriage, holding that marriage is only between man and wife.
Tomorrow he travels to the central Philippines to comfort survivors of the 2013 Typhoon Haiyan, which left more than 7,300 dead and missing and levelled entire villages.
The government has declared national holidays during the Pope's visit, which culminates on Sunday with a mass in Manila's huge Rizal Park, and the crowds responded by turning out in droves to welcome him. Authorities estimated that between 700,000 and a million people lined his motorcade route in from the airport last night.
He was clearly energised by the raucous welcome, stopping several times to kiss children brought up to him once he entered the presidential palace grounds. His motorcade did not stop along the route, though, for him to get out to greet the crowd as he likes to do.
It remains to be seen if he will chafe at the intense security provided by authorities, who appeared to leave nothing to chance. They have good reason to go overboard after Pope Paul VI was slightly wounded in an assassination attempt during his visit in 1970, and St John Paul II was the target of militants whose plot was uncovered days before his 1995 arrival.
About 50,000 police and troops have been deployed to secure the Pope in a country where relatively small numbers of al Qaida-inspired militants remain a threat in the south despite more than a decade of US-backed military offensives.