Donald Trump and Pope Francis are poles apart, but they were linked together by the same headlines recently when the Pontiff declared that anyone who deliberately builds walls cannot be described as a Christian.
Although the Pope had not mentioned Trump specifically, his remarks hit home. The contrast between the gentle man of words and the bombastic, egotistic politician could not have been more marked.
One of Trump's election pledges is that, if elected as US President, he will build a wall between the USA and Mexico to keep out the immigrants, and that the Mexicans will pay for it.
It is obviously a grandiose election claim to impress those of his followers who do not think too deeply, which covers the vast majority of them. Trump, like Boris Johnson, is a street-wise operator who indulges in political circus acts to disguise his real intentions, but surely even he can hardly believe that his madcap Mexican project is anything more than a fantasy.
Nevertheless, it is frightening that this man looks like becoming the Republican candidate in the US Presidential election, and that one day he may be in control of nuclear missiles.
Political observers, who are more often wrong than right, claim that this will not happen, but they were wrong about the rank outsider Jeremy Corbyn becoming leader of the Labour Party.
In such a topsy-turvy world, it is important that we still have thoughtful and wise people in high places, like Pope Francis. His remarks about the divisive attitude of building walls could apply not only to Donald Trump, but to all of us.
The so-called "Peace Walls" in Belfast are not a good example of a truly Christian society, and we also build walls in our minds, and in the way we live.
In the impassioned debate about the future of the UK in Europe, there is a fear in many people's minds about excessive migration into this country.
Few want to admit their opposition to this publicly, but it may be a deciding factor in a debate during which the Out camp - including the DUP - has yet to present a convincing analysis of what would happen if the UK leaves Europe.
There are many other examples of walls which we build every day, some deliberately and others almost inadvertently.
We build walls in family life, and everyone knows of divisions where members never speak, and only meet at family baptisms, weddings and, most usually, funerals.
We build walls in our Church life. How many Protestants here refuse to darken the door of a Roman Catholic Church, and vice-versa, and how many Protestants will hardly even attend a service of another Protestant denomination? What about people who use liturgy as a wall that divides rather than supports?
We also build walls in our personal lives. How many people do we choose not to talk to, or to cross the street to avoid? How many letters have we deliberately left unanswered, and how many e-mails or social media messages from other people do we ignore?
There was a time when such things were answered as simply good manners, but we live in an extremely rude age when too many people routinely decide not to reply to messages they don't like, not even to say "No".
So before you totally condemn the likes of Donald Trump, think also about yourself. If we consider seriously Pope Francis' words about building walls, we might conclude there are very few Christians left anywhere.