It's the 21st-entury equivalent of the New Testament admonition that "the love of money is the root of all evil" in an age when critics say the globalized capitalist system is rigged against the poor.
In the American context, however, Francis' statement was like tossing a match onto a field of dry hay.
Religious conservatives in the U.S. were already anxious about the pope's efforts to reorient the Catholic agenda toward a priority on social justice for the poor. And political conservatives are especially worried that Francis' frequent blasts at income inequality are playing into the hands of President Barack Obama and the Democrats, who have also made the wealth gap a major talking point.
Add in the current agita on the right about French economist Thomas Piketty's best-selling book on the income divide, "Capital in the 21st Century," and, whoosh, instant social media wildfire.
"Seriously, though, what was up with that tweet by @Pontifex? Has he traded the writings of Peter and Paul for Piketty?" tweeted Joe Carter of the Acton Institute, a Catholic-run, libertarian think tank.
"Hate and apathy are the roots of social evil," he added as a counterpoint.
"So, if we achieve maximum redistribution of resources, we will have eliminated 'social evil,' whatever that is?" wrote Rod Dreher in a rather snarky post at the American Conservative. "Yes, and that's why the Soviet Union was the Garden of Eden."
"Piketty gets a blurb," tweeted Matthew Schmitz, deputy editor of the conservative journal First Things.
At Catholic Culture, a conservative news site, editor Phil Lawler called the pope's tweet "a fairly radical statement" and as "a piece of economic analysis a very simplistic one." He added that Francis probably doesn't know what's going onto his Twitter feed anyway, and the pope definitely does not speak English.
"So we can be sure those aren't his exact words," Lawler said, echoing previous conservative efforts to downplay or explain away some of Francis' more provocative statements.
Yet Vatican officials have said that in fact Francis personally approves all of his tweets, and did so in this case as well. Moreover, they noted that the tweet is taken directly from Francis' blockbuster exhortation from last year, The Joy of the Gospel (see paragraph No. 202).
So what explains the high anxiety?
One reason is that Catholic conservatives were already on edge after trying to sort out what exactly Francis said to an Argentine woman he called to discuss her irregular marital situation and whether she could receive Communion. It seemed the pope told her she could, and many worried that this sent the wrong signal, and that Francis should stop communicating so casually via cold calls and social media.
"Another unnecessarily ambiguous therefore controversial papal statement," Dreher tweeted after Monday's message from Francis. "Twitter bad for clear papal communication."