He added that he does not endorse candidates -- he is simply giving Trump guidance.
"I encouraged him, while assuring him of our love for him and his family, and concern for America's future," Robison wrote.
"But I also spoke bluntly and forcefully about where I'm convinced he needs to make essential changes in his approach and rhetoric while gaining the wisdom that comes from above to become the effective leader necessary to correct our nation's dangerous course."
Carson told Yahoo News that Christian voters probably won't find Trump's conduct on the recording acceptable, but he said that Trump is still a better option than the Democratic nominee.
"I'm a Christian voter and I'm not OK with it, but I can look at the bigger picture, and I think a lot of other Christians can look at the bigger picture too," Carson told Yahoo News.
"I can't defend the video, but I can certainly continue to support him because I think what he represents is far superior to what Hillary represents."
See photos of Ben Carson on the campaign trial:
Ben Carson on the campaign trail
Ben Carson on the campaign trail
MT. AYR, IA - JANUARY 22 : Republican presidential candidate Ben Carson is introduced during his 'Trust in God Townhall' campaign stop January 22, 2016 in Mt. Ayr, Iowa. Carson, who is seeking the nomination from the Republican Party is on the presidential campaign trail across Iowa ahead of the Iowa Caucus taking place February 1. (Photo by Joshua Lott/Getty Images)
Ben Carson, 2016 Republican presidential candidate, speaks during a Liberty University Convocation in Lynchburg, Virginia, U.S., on Wednesday, Nov. 11, 2015. As retired neurosurgeon Carson has risen in the polls, media reports have revisited his accounts of acts of violence as a child, a key part of the redemption story he discusses on the campaign trail. Photographer: Andrew Harrer/Bloomberg via Getty Images
PALM BEACH GARDENS, FL - NOVEMBER 06: Republican presidential candidate Ben Carson speaks to the media before speaking at a gala for the Black Republican Caucus of South Florida at PGA National Resort on November 6, 2015 in Palm Beach, Florida. Carson has come under media scrutiny for possibly exaggerating his background and other statements he has made recently. (Photo by Joe Raedle/Getty Images)
DES MOINES, IA - AUGUST 16: Republican presidential hopeful Ben Carson (L) eats a piece of pizza while touring the Iowa State Fair on August 16, 2015 in Des Moines, Iowa. Presidential candidates are addressing attendees at the Iowa State Fair on the Des Moines Register Presidential Soapbox stage and touring the fairgrounds. The State Fair runs through August 23. (Photo by Justin Sullivan/Getty Images)
LAKEWOOD, CO - OCTOBER 29: Republican presidential candidate Ben Carson speaks during a news conference before a campaign event at Colorado Christian University on October 29, 2015 in Lakewood, Colorado. Ben Carson was back on the campaign trail a day after the third republican debate held at the University of Colorado Boulder. (Photo by Justin Sullivan/Getty Images)
WASHINGTON, DC - SEPTEMBER 25: Scenes around the the Value Voters Summit on September 25, 2015 in Washington DC. Republican presidential candidate Ben Carson takes the stage at the event. Dr Carson speaks to the media after the speach. (Photos by Charles Ommanney/The Washington Post via Getty Images)
Attendees wait for Ben Carson, 2016 Republican presidential candidate, not pictured, to arrive during a campaign stop at the birthplace of the Michigan Republican Party in Jackson, Michigan, U.S., on Wednesday, Sept. 23, 2015. Carson, the third candidate in the Republican race to have never held elected office, saw his numbers drop following the debate last week. Photographer: Luke Sharrett/Bloomberg via Getty Images
Ben Carson, 2016 Republican presidential candidate, listens as he attends a service at Maple Street Missionary Baptist Church in Des Moines, Iowa, U.S., on Sunday, Aug. 16, 2015. Carson will be speaking at the Iowa State Fair, which is expected to host 18 presidential candidates and runs until Aug. 23. Photographer: Daniel Acker/Bloomberg via Getty Images
CLEVELAND, OH - AUGUST 06: Republican presidential candidate Ben Carson participates in the first prime-time presidential debate hosted by FOX News and Facebook at the Quicken Loans Arena August 6, 2015 in Cleveland, Ohio. The top-ten GOP candidates were selected to participate in the debate based on their rank in an average of the five most recent national political polls. (Photo by Chip Somodevilla/Getty Images)
Ben Carson, 2016 Republican presidential candidate, eats a slice of pizza as he tours the Iowa State Fair in Des Moines, Iowa, U.S., on Sunday, Aug. 16, 2015. In a Sunday interview with Fox News, Carson doubled down on his assertion that a speech given by President Barack Obama intended to sell the American public on his nuclear deal with Iran contained 'coded innuendos employing standard anti-Semitic themes.' Photographer: Daniel Acker/Bloomberg via Getty Images