Buses and cars on Friday shuttled Morsi's backers to Rabaa al-Adawiya Square, centre of demonstrations in support of the Islamist leader since his overthrow on July 3.
"I am here to support the real president of Egypt, we are going to protest here peacefully," El-Baz Abu Maati, who had just arrived from the Nile Delta city of Mansura, told Agence France-Presse, as hundreds of Morsi supporters streamed past him, making their way calmly to the square.
Guards at the entrance to the protest camp patted people down and searched bags for weapons as the crowds arrived, checking ID cards.
Nearby, men wearing hard hats and carrying makeshift clubs watched over the new arrivals anxiously.
Thousands were already massed in the square itself, where the mood was mostly subdued as Morsi's supporters waited in the scorching heat for the rally to begin.
Some stole a few moments sleep before the rally, while others read from the Qu'ran.
The fugitive leader of the Muslim Brotherhood, Mohamed Badie, on Thursday urged Egyptians to rally "against the bloody coup" that ousted Morsi, but to do so peacefully.
Fight 'terrorism and violence'
Badie's call came after army Chief General Abdel Fattah al-Sisi had earlier called for rallies on Friday to give him a mandate to fight "terrorism and violence".
Many at Rabaa al-Adawiya Square repeated that they wanted to protest peacefully.
"We are not afraid of the army, and we have the legal right to do anything," said Magdy Ahmed, who had come from Minya.
"We are peaceful," he stressed, patting himself down to show he was carrying nothing other than the prayer mat he had brought to sit on.
However, Abbas al-Ibrahim was adamant he would defend himself against any attack on the peaceful demonstration.
"We will kill everyone who kills our freedom," he shouted.
"We voted for this president [Morsi] … now we will die in this place to secure his return," he added.
Nearly 200 dead
Political unrest across Egypt has killed nearly 200 people since the massive protests on June 30 that led to Morsi's overthrow.
Both sides have traded accusations that they have been attacked by the other.
Past the entrance to the square, vendors were doing a brisk trade selling Morsi masks, badges and posters, one of which read "Friday of victory – victory is close".
A small group crowded around a battered truck loaded with speakers playing Hold Your Head High, You're Egyptian, a song urging unity between all Egyptians.
The group danced and waved Egyptian flags as they sang, while men carrying tanks of water on their backs sprayed crowds to cool them down.
Others arriving in the square chanted "Islamic, Islamic" as they headed to the main stage in the square. One of the group held a copy of the Koran above his head, chanting: "We have no weapons other than this".
Ahmed Helmy (50), a university professor, had come to voice his outrage at the military-backed overthrow of Morsi, travelling from the central province of Asiut at four in the morning.
"We have been waiting for more than 60 years for the first civilian, elected president since the military coup of 1952," he said.
'I care about this country​'
Student Omar Abou El-Khair (19), from the United States, had travelled from Mansura, where he was visiting his family during his university holidays.
"What Sisi did was a military coup, it was nothing like the first revolution," he said.
"I come to Egypt every two years because I care about this country, and what goes on here. That's why I'm spending my vacation here instead of chilling on a beach somewhere". – AFP