Christian conservative Franklin Graham has called on presidential hopeful Pete Buttigieg to repent for being gay, warning that he faces eternal damnation for “flaunting” his sexuality.

At a recent CNN town hall, Buttigieg addressed critics who say being gay is inconsistent with Christianity.

“It can be challenging to be a person of faith who's also part of the LGBTQ community and yet, to me, the core of faith is regard for one another,” said Buttigieg, the openly gay mayor of South Bend, Indiana. “[P]art of God's love is experienced – according to my faith tradition – in the way that we support one another and, in particular, support the least among us.”

(Related: Bryan Fischer: Pete Buttigieg's sexuality disqualifies him from being president.)

In a series of tweets, Graham, the son of the late televangelist Billy Graham and a supporter of President Donald Trump, called on Buttigieg, who last year married his husband Chasten, to repent.

“Presidential candidate & South Bend Mayor @PeteButtigieg is right – God doesn't have a political party,” Graham messaged. “But God does have commandments, laws & standards He gives us to live by. God doesn't change. His Word is the same yesterday, today & forever.”

“Mayor Buttigieg says he's a gay Christian. As a Christian I believe the Bible which defines homosexuality as sin, something to be repentant of, not something to be flaunted, praised or politicized. The Bible says marriage is between a man & a woman – not two men, not two women.”

“The core of the Christian faith is believing and following Jesus Christ, who God sent to be the Savior of the world – to save us from sin, to save us from hell, to save us from eternal damnation,” he added.

Buttigieg's popularity has rocketed in recent weeks, placing him third among Democratic presidential candidates behind former Vice President Joe Biden and Vermont Senator Bernie Sanders.

(Related: New poll has Pete Buttigieg closing in on Joe Biden, Bernie Sanders.)