Carl Gallups has a simple message for Christians worried about voting for Donald Trump in 2016 – it's either Trump or Hillary. And it really is that simple.

The well-known pastor and author of several books including "Be Thou Prepared: Equipping the Church for Persecution and Times of Trouble" recently appeared on Susan Knowles' Stand for Truth radio program to discuss the presumptive Republican nominee and the criticisms some Christian leaders have raised about him.

One of the first subjects discussed was Russell Moore, head of the Southern Baptist Convention's Ethnics and Religious Liberty Commission. Moore has been a vocal critic of Trump and has urged Southern Baptists not to support the presumptive Republican nominee.

Gallups charged Moore has consistently opposed those who favor strong controls on immigration, even going as far back as Pat Buchanan. Gallups identified the WND columnist, best-selling author and former presidential candidate as a precursor to Trump. And Gallups said Trump's advocacy for sensible immigration control should be a top concern of all Americans, especially Christians.

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"Pat Buchanan was saying, look, we've got to get a grip on our border," Gallups recalled. "This is causing a crisis, this is going to destroy our country, it's going to water us down, it could literally destroy us. Well, along comes Donald Trump saying the same kinds of things, I think perhaps maybe even more measured than what Pat Buchanan said. And Donald Trump is saying in light of the Middle East exploding with Islamic terrorism, in light of the fact that we've already been attacked on September 11, 2001, in New York City, let's not be insane about this."

Gallups said the threat of the Islamic State should not be understated, and he argued Christians simply need to listen to the group's own words to understand its strategy.

"There is a group that desires to destroy us and because of what's happening in the Middle East, ISIS is now bragging about using the refugee crisis as a Trojan Horse to infiltrate Europe with their ISIS operatives," Gallups observed. "The FBI now admits, publicly, in mainstream media, that they are tracking ISIS terrorist cells in all 50 states of the United States. We know that ISIS agents are trying to gain entrance to the United States through our southern border."

The pastor and former law enforcement professional argued it takes a strong commander in chief to protect against such a threat. Barack Obama, he suggested, is not that man.

"Barack Obama has what I believe to be this insane policy of importing tens of thousands of Syrians and Muslim Middle Eastern refugees and dispersing them throughout the United States," Gallups commented. "Conveniently, it has been exposed in some reports, into traditionally conservative areas of the country, dispersing these people amongst our population. Obama is suing Sheriff Joe Arpaio and other local officials who are trying to enforce our federal border laws and immigration laws. And Trump comes along and says, 'We have to stop the madness! I don't hate Muslims, I don't hate immigrants, I am all for legal immigration ... but we've got the hold back the flood of the Islamic refugees and immigrants until we know who's who. We don’t even have a vetting process!'"

Gallups condemned "our insane immigration policies over the last eight years of this administration."

In contrast, Gallups called Trump's position on immigration "pure common sense" and argued the Constitution requires the federal government to actually enforce immigration law.

"Instead," Gallups sighed, "the federal government has decided it's more important to make sure men can go into the little girls' room."

The pastor acknowledged some Christians have argued the refugee crisis allows the Gospel to be taken to new people. However, Gallups said a strong America built upon a Judeo-Christian foundation is ultimately necessary if American Christians are to be effective in spreading their faith. If America collapses, Gallups warned, "We won't have the ability to take the Gospel to anyone, much less to refugees who are among us."

Persecution is coming – are you and your family ready? "Be Thou Prepared" by Carl Gallups, available now in the WND Superstore.

He argued mass immigration, especially by Muslims, could dramatically transform the core culture and even the legal system of the country.

"The [Islamic] refugees can overwhelm us and take control of our legal system and shut us [Christians] down," said Gallups. "And if you don't believe it, you can ask the people in Europe. It's happening to them right now."

However, as Susan Knowles stated, many Christians are concerned about Donald Trump because of questions about his temperament and morality. Gallups said he shared some of those reservations.

"I'm very disappointed in much of what I see and hear from Donald Trump," said Gallups.

Gallups said he hoped Trump would show himself to be more presidential in his behavior as the campaign continues.

But Gallups said the stakes are too high for Christians to stay home or vote third party.

"If we stay at home, and millions of conservatives don't vote, that's why we had Obama in office for two terms," Gallups charged. "That's why we have gay marriage. That's why we now have the transgenderism bathroom decree for public schools across America. Because millions of Christians stayed home and didn't vote.

"If you write in a third party, you have voted for the Democrat Party, in pragmatic, statistical reality. I deal in pragmatics and reality, and it's the statistical truth."

Gallups also encouraged Christians not to become self-righteous about voting, saying the only choice which has ever existed is voting for the lesser or the greater of two evils.

"Christians say, 'Well, I'm voting for the lesser of two evils' – well, yes you are," he admitted. “Yes you are. But you always have and you always will – until Jesus returns. If you don't vote, or you vote for a third party which will not and cannot win, then you have literally, actually voted for the greater of the two evils. Don't get caught up in this politically correct speech, this paralysis by analysis, until you end up helping the very thing you think you are standing against."

Gallups urged Christians to understand living in a fallen world means making tough choices and, unfortunately, it isn't "clean" or simple.

"We can't live on a hill with a white robe and a halo over our heads saying, 'I'm going to be separate from it all,'" he said. "To Christians who say, 'I can't vote for Donald Trump because his moral rectitude doesn't measure up to mine,' here’s my question: 'Who do you work for? Do you work for the school system? Do you work for a corporation? Do you work for a law firm? Do you work for a government office? Are your bosses all in line with your views? Why don't you quit? Why don't you vote your conscience?'

"Don’t be self-righteous about who is going to be president and live the rest of your life making compromises every day. People have got to wrap their heads around reality. We live in Babylon. We, as Christians, need to get some breathing room."

Persecution is coming – are you and your family ready? "Be Thou Prepared" by Carl Gallups, available now in the WND Superstore.