It also left many traditional and faithful Catholics perturbed about his obvious sympathies in the context of reform. The Pope highlighted three “key concepts” from that day’s Gospel reading in which Jesus heals the leper, linking them to “the compassion of Jesus in the face of marginalization and his desire to reinstate” lives.

In essence, he equated the leper, an outcast in Jesus’ day, with those who, because of sin, stand outside the church. Francis would like to attract them by, above all, placing an emphasis on God’s mercy rather than their sins and repentance of them.

This theme of the homily, which highlighted inclusiveness, nondiscrimination, and going out to the peripheries, is central not only to this pontificate but was a key aspect coming out of last October’s synod on the family.

That meeting in Rome of around 250 bishops worldwide was meant to examine today’s pastoral challenges to the family, but it drew controversy for proposing new pastoral practices towards civilly remarried Catholic divorcees, homosexuals, and cohabiting couples — approaches that many felt were at odds with Catholic teaching.

With this homily, observers on all sides of the church say it’s confirmed where the Pope stands on these issues. In an article for The Remnant, a newspaper of traditional Catholicism, an author writing under the Greek goddess name of Megaera Erinyes, says Francis is “clearly signaling again” his intentions for the Synod, and the terms he uses show he is “wholly on the side” of Cardinal Walter Kasper, the flag-bearer of those pushing to allow divorced and civilly remarried Catholics to receive Holy Communion.

The scriptural passages in which Jesus teaches that remarriage after divorce constitutes adultery couldn’t be clearer, Erinyes argues. Yet, by implicitly supporting the Kasper line in his homily (Francis’ doesn’t directly mention the issue) she believes the Pope sees obedience to Jesus’ teaching on this issue as a “lack of mercy” and “marginalization.”

Rather than a merciful approach, she argues the Kasper position actually shows disobedience to the divine law and therefore a “hardness of heart” that Jesus’ teachings aimed to remedy. That the Pope sides with this position “is a frightening thought,” she writes.

For Austen Ivereigh, author of “The Great Reformer,” possibly the most comprehensive biography of Pope Francis to date, the homily was not so clear cut. He agreed it will be seen, “as one of the most defining messages of his pontificate” and it “certainly is aimed at the synod.” But he said it also captures the way Francis “sees his mission more broadly, as opening new paths for people to find their way back to the church.”

“He’s saying: it’s not enough to preach the truth and wait for people to convert and come knocking — we have to go out and tend to the lost sheep, and let God do the rest,” Ivereigh told me. “It would be wrong to read into it an endorsement of one or other strategy under discussion at the synod, although it is a clear rebuke of those who are opposed to the whole process.”

Other aspects of the homily have also caused concern, especially its central theme of equating the outcast leper with a sinner — cast out from the church. Erinyes calls this a “false premise,” a “simple rhetorical fallacy” and a “conflation” between the affliction of illness and the consequences of sin.

“A leper is someone who suffers from a disease, who does indeed need a doctor,” she writes. “A man living with a woman to whom he is not married has entered into this situation with his will. And it is with his will he can remedy the situation. He can decide, today, to sin no more, and to change his life.”

Further questions about the homily relate to the Pope’s chastisement of “doctors of law,” and his poor perception of those who “fear to lose the saved” compared to those who want “save the lost.”

Ivereigh said the Pope is contrasting two mentalities, and sees the former as reminiscent of the Pharisees of Jesus’ time (their starting point is a sense of threat to the integrity of the faith) and the latter as “Jesus in the Gospel”, starting with the pain of those “outside the channels of salvation”. For Francis, the way of the Gospel “is always to seek reinstatement through the exercise of mercy,” Ivereigh said. “It’s wrong to see this as disregard for the law.”

But Erinyes calls this a classic “false dichotomy,” and that to offer the marginalized something meaningful while “abandoning the existing flock” is an “odd and contradictory statement.”

The Pope appears to think that someone who “holds their faith in its entirety” is, by nature, “cruel and exclusionary,” she says. “But this is logically absurd, since it is that faith, that divine law, that requires (genuine) mercy and compassion for both the sick and the sinner.”

Such contentious arguments are likely to continue and strengthen as the October synod approaches. By Francis revealing his thoughts now on these issues (he earlier hadn’t done so in the interests of a free discussion) it makes it arguably harder for those opposed to them to speak out without setting themselves against the Pope.

But given how much is at stake — Erinyes says the Kasper proposal represents a one-blow strike “against the very pillars of the faith: the Eucharist and the priesthood” – signs suggest there will be more than a little resistance come October.