The man at the centre of the "gay cake" case is bearing a "heavy burden" because of the legal battle, his lawyer said.
The Christian owners of Ashers Bakery were found to have discriminated by refusing to make a product iced with the slogan Support Gay Marriage.
The order was placed by gay rights activist Gareth Lee in May 2014 and was the subject of a Supreme Court appeal in Belfast this week.
His barrister Robin Allen QC said: "This is what was a relatively small incident in his life which has become enormously significant and continues to be so.
"That is a heavy burden to bear for one individual."
The Ashers legal action has run for four years and attracted enormous attention.
The original case against the McArthur family, who own Ashers and enjoy the backing of the Christian Institute lobby group, was taken by Mr Lee with the support of Northern Ireland's Equality Commission.
The bakers lost in the lower courts.
Mr Allen said the Commission was seeking "legal certainty" and stepped in because only a millionaire could afford to litigate this case.
"In the context of this case it is super-difficult because in relation to the provision of goods, facilities and services you are talking about a prohibition on discrimination on transactions which may range from a box of matches up to a long-term contract.
"In many cases, particularly true in a divided community, prohibition in relation to goods and services is a task which is difficult to police through a commission or litigation."
Earlier today Northern Ireland's attorney general said the Court of Appeal was wrong in its treatment of the couple.
Attorney general John Larkin QC said: "The Court of Appeal were quite wrong to see the McArthurs in some way as the authors of their own misfortune, with the forced speech arising only from their wide offer."
Counsel for Daniel and Amy McArthur, who own Ashers, has argued that the state is penalising the Belfast baking firm, with the courts effectively compelling or forcing them to make a cake whose message they disagree with as a matter of religious conscience.
Mr Larkin said offers in printed material from Ashers' owners around celebration cakes for sporting organisations which they did not support were incomparable to the gay marriage refusal.
He added: "There is a global difference between that and a highly charged political message."
He said it had been "unimaginable" at the time the brochure on celebratory cakes was produced that someone would request the message Support Gay Marriage.
The five Supreme Court judges hearing the case were Lord Hodge, Lord Mance, Lady Hale, Lord Kerr and Lady Black.
The Ashers legal battle has run for four years and attracted enormous attention.
The original action against the McArthurs, who enjoy the backing of the Christian Institute lobby group, was taken by Mr Lee with the support of Northern Ireland's Equality Commission and the bakers lost in the lower courts.
Northern Ireland is the only part of the UK or Ireland where same-sex marriage is outlawed, with Theresa May's DUP allies staunch opponents of the practice.
Controversy first flared when Mr Lee, a member of the LGBT advocacy group Queer Space, requested a cake featuring Sesame Street puppets Bert and Ernie for a private function marking International Day Against Homophobia.
His £36.50 order was accepted and he paid in full but, two days later, the company called to say it could not proceed due to the message requested.
One of the Supreme Court judges, Lady Hale, said people should not expect their answer on the case immediately.
"This is not to say that we don't hope that it might be before the summer but these cases are by definition complex and difficult and there are five people who have to make their minds up so that... takes more time than simply the jury verdict, even at the end of a long trial."
