Pakistan's ousted chief justice has told a crowd of thousands in Lahore that dictatorships which ignore the rule of law face "destruction".
Iftikhar Chaudhry's motorcade was swamped by supporters
Iftikhar Chaudhry made no direct reference to President Pervez Musharraf who suspended him in March over allegations of abuse of office.
Anger over his sacking poses the biggest challenge to Gen Musharraf's rule since he seized power in 1999.
Supporters waved flags and shouted slogans against the president.
Mr Chaudhry says he is fighting for the independence of the judiciary but the protests in his favour have turned into a broader campaign against military rule, says the BBC's Barbara Plett in Islamabad .
The chief justice reached the Lahore High Court at 0830 (0430 GMT), to be greeted by a crowd including thousands of lawyers and political activists, as well as high court judges and 18 retired senior judges.
Mr Chaudhry was suspended from his post in March
Lahore is the headquarters of Pakistan's legal community so such a turnout is an important boost to Justice Chaudhry's campaign, our correspondent says.
"Nations and states which are based on dictatorship instead of the supremacy of the constitution, the rule of law and protection of basic rights get destroyed," Mr Chaudhry told the crowd in the compound of the Lahore High Court.
"The idea of dictatorship and collective responsibility are over... and those nations which don't learn lessons from the past and repeat those mistakes, they have to pay a price," he said in words quoted by Reuters news agency.
Coming from Islamabad, Justice Chaudhry's motorcade had been slowed down by supporters who threw rose petals, beat drums and set off fire crackers.
Chants of "Go, Musharraf, go!" were heard as he crossed the bridge over the River Ravi to approach Lahore. It took him 24 hours to travel a distance that usually takes four.
It was a massive show of support even though police arrested political workers, blocked roads and in some cases fired tear gas.
About 7,000 security personnel were deployed for the rally.
A number of rallies have been held since Mr Chaudhry was suspended on 9 March but Lahore, the capital of Punjab province, is the most significant of the cities he has visited, our correspondent says.
Not only is it the headquarters of Pakistan's legal community, it is also the base of President Musharraf's political party, the Pakistan Muslim League, she adds.
Mr Musharraf earlier warned lawyers not to politicise the issue.
"This is a constitutional and judicial issue and those giving it a political tone will not be successful in their designs," he said.
It has been alleged that Mr Chaudhry illegally used his position in an attempt to procure a top police job for his son.
Mr Chaudhry, who became chief justice in 2005, has earned a reputation for challenging human rights abuses and government wrongdoing.