Taking Syria's seat at the Arab League gathering in Qatar for the first time, Syrian opposition leader Moaz Alkhatib pulled no punches in his appeal to the assembled emirs and presidents, who are often criticised by human rights groups for their handling of domestic dissent.
"As your youngest brother, I tell you: fear God while dealing with your people, reinforce your country with fairness and justice," the Sunni Muslim cleric said, acknowledging that he was breaking away from diplomatic protocol.
Alkhatib called on the leaders to adopt a resolution "to free detainees in all of the Arab world so that the day of the victory of the Syrian revolution, which will break a link of repression, is a day of joy for all our peoples".
It was an eye-catching request to make of the countries who in large part fund the opposition's two-year-old struggle to topple Syrian President Bashar al-Assad.
Many Arab states deny holding political prisoners, saying they only detain lawbreakers or those who threaten national security. Where abuses occur, they are investigated, officials in many such countries say. On Monday Egypt's prosecutor general ordered the arrest of five prominent political activists pending questioning about violence near the Muslim Brotherhood's headquarters last week.
Last month a Qatari poet was sentenced to 15 years in jail for criticising the emir and attempting to incite revolt.
Alkhatib's request echoed the emphasis in his summit speech on the need to respect human rights and end violence against innocents, sentiments voiced frequently by demonstrators who have driven the Arab uprisings of the past two years.
The former mosque preacher highlighted what he called atrocities committed by Syrian government forces against rebels and dissidents, describing how one of his students had been driven mad by a week of torture before he was killed.
Alkhatib also called on Washington to take a greater role in the Syrian crisis and said he had asked U.S. Secretary of State John Kerry to use Patriot missiles to protect rebel-held parts of northern Syria from Assad's air power.