A Colorado Christian baker is asking the U.S. Supreme Court to reverse a 2012 ruling that found him guilty of discrimination for refusing to make a wedding cake for a same-sex couple because of his religious beliefs.

The Alliance Defending Freedom (ADF) has filed the motion with the High Court on behalf of Jack Phillips, owner of Masterpiece Cakeshop, saying the U.S. government cannot force him to convey a message that he disagrees with.

The petition rests on the argument that the decision violates his free speech and free exercise clauses under the First Amendment.

In December 2013, the Colorado Civil Rights Commission ruled that Phillips engaged in discrimination under the Colorado Anti-Discrimination Act (CADA).

Last April, the Colorado Supreme Court denied a plea to hear Phillips' case after the state Court of Appeals affirmed the decision of the civil rights commission.

The commission ordered Phillips to make cakes for same-sex marriages, comply with the CADA by re-educating his shop's staff and file quarterly compliance reports for two years.

"No one—not Jack or anyone else—should be forced by the government to further a message that they cannot in good conscience promote," said ADF senior counsel Jeremy Tedesco. "We are asking the U.S. Supreme Court to ensure that government understands that its duty is to protect the people's freedom to follow their beliefs personally and professionally, not force them to violate those beliefs as the price of earning a living."

The case stemmed in July 2012 when Charlie Craig and David Mullins asked Phillips to make a wedding cake to celebrate their same-sex marriage.

Phillips politely declined because of his faith.

The gay couple later filed a complaint with the Civil Rights Commission, which ruled against Phillips.

The ADF said last year, the commission found three other Denver cake makers not guilty of discrimination when they refused a Christian customer's request for a cake that reflected his religious opposition to same-sex marriage.

"It is undisputed that the Colorado Civil Rights Commission...does not apply CADA [Colorado Anti-Discrimination Act] to ban (1) an African-American cake artist from refusing to create a cake promoting white-supremacism for the Aryan Nation, (2) an Islamic cake artist from refusing to create a cake denigrating the Quran for the Westboro Baptist Church, and (3) three secular cake artists from refusing to create cakes opposing same-sex marriage for a Christian patron," the petition states.

"Neither should CADA ban Jack Phillips' polite declining to create a cake celebrating same-sex marriage on religious grounds when he is happy to create other items for gay and lesbian clients," the petition adds.