And his Unholiness is right - Trump isn't a Christian. Matthew 7:15-20 states it quite clearly:
“Beware of the false prophets, who come to you in sheep’s clothing, but inwardly are ravenous wolves. You will know them by their fruits. Grapes are not gathered from thorn bushes nor figs from thistles, are they? So every good tree bears good fruit, but the bad tree bears bad fruit. A good tree cannot produce bad fruit, nor can a bad tree produce good fruit. Every tree that does not bear good fruit is cut down and thrown into the fire. So then, you will know them by their fruits.
Trump's hyper-prideful "fruit" indicates a great many things about him, but that he's a true Christian isn't one of them.
The punchline is, neither, really, is Francis. Which makes this a "takes one to know one" dynamic:
U.S. Republican presidential candidate Donald Trump is "not Christian" because of his views on immigration, Pope Francis said on his way back to Rome from Mexico....
In a freewheeling conversation with reporters on his flight back from a visit to Mexico, Francis was asked about Trump and some of his statements, such as vowing to build a wall between the United States and Mexico if he becomes president.
"A person who thinks only about building walls, wherever they may be, and not building bridges, is not Christian," Francis said in answer to a specific question about Trump's views. "This is not in the Gospel."
Actually, there's nothing in the Gospel about immigration policy at all, so what that statement amounted to was Francis accusing Trump of not being leftwing and disguising it in religious rhetorical imagery. Now what's "not Christian" about Trump is that by promising to build a wall between the U.S. and Mexico, he's bearing false witness because the man who has benefited handsomely from cheap illegal alien labor in his various and sundry business endeavors has no intention of following through on his bellicose immigration rhetoric but is only dispensing it to bilk Republican voters into supporting him. But Francis can't point that out either because he's fallen for Trump's lies or because he's in on the scam himself as a loyal, card-carrying member of the far Left. Which would render him "not Christian" as well.
Trump's faux indignant but trademark reaction to the Pope's accurate-but-not-in-the-way-he-thinks accusation wasn't exactly a "softeth answer":
Asked about the comments, Trump said they were ""really not a nice thing to say." and that attacking someone's faith is "disgraceful."
He also said, "If it's good, I like the Pope, if it's bad, I don't like the Pope."
Trump later said Pope Francis would regret those words "if and when" ISIS attacks the Vatican. [emphasis added]
What's THAT supposed to mean? That if a Trump administration got wind of an imminent ISIS attack plot against Vatican City, he would stand back and let it happen in order to "teach the Pope a lesson"? Vicarious revenge? Or is he claiming that he's the only candidate serious about stopping ISIS? The former would be a murderous level of butthurt, that latter more false-witness bearing. In addition to being a non sequitur to the issue on which Francis was attacking Trump in the first place.
If you ever wondered what it would look like when two false prophets quarreled, now you have your answer.