In a campaign video released on Saturday, just days before Ted Cruz bested him in the Iowa caucuses, Republican presidential candidate Donald Trump thanked Evangelical Christians for their support and spoke about his personal connection with the family Bible.

The video, entitled “Christian Values” and posted to Trump’s Facebook page, features Trump addressing Evangelical Christians directly. “I really appreciate the support given to me by the Evangelicals. They’ve been incredible. Every poll says how well I’m doing with them,” Trump says.

He then displays his family’s heirloom, a copy of the Bible which he says belonged to his mother, pointing out her writing in the front endpaper. “She wrote the name, and my address, and it’s just very special to me,” he tells the camera.

Trump, who is a frontrunner in the race for the Republican presidential nomination, ends the 36-second video with a firm promise to his supporters. “Again, I want to thank the Evangelicals. I will never let you down,” he vows.

The global business magnate’s relationship with Evangelical Christians has been a subject of much interest and analysis as the presidential race approaches primaries, with many wondering if the important demographic’s support of Trump’s campaign would translate to votes.

Trump’s first true test of his Evangelical support may reveal some weaknesses. While Iowa has a significant Evangelical population, Trump’s popularity among them did not bring him success in the first leg of the race for the GOP presidential nomination. Rival Ted Cruz, a strong ideological conservative candidate, pulled ahead of Trump’s 24 percent of the vote with a larger share of 27.7 percent.