(CNN) Fighters must be given amnesty if peace in Colombia is to succeed, the rebels' chief negotiator told CNN en Español.
"Without this law, well, it is very difficult for the guerillas to begin their movement into the peace zones or to the transitional points for normalization," Ivan Marquez told Fernando Ramos in an exclusive interview.
Marquez said "assurances" were vital if the Revolutionary Armed Forces of Colombia (FARC) were to lay down their weapons to end the continent's longest-running war. But he also struck an optimistic note, saying he believed Colombians -- friends and former foes -- would "surround them with affection."
"The people want peace," he said. "This is something that has been sought out for so long and this is the opportunity... I believe that the Colombian people have to hold on to this hope that we will have a future; so that we can have peace with dignity."
Marquez signed a preliminary peace deal with a government counterpart in Havana in August. The deal will now get a formal signing on Monday and must then be approved by the Colombian people in a referendum set for October 2.
The outcome is not certain -- the call for amnesty for the guerrillas involved in the war that killed up to 220,000 people and forced millions more from their homes is particularly controversial.
Former President Alvaro Uribe Velez opposes the peace deal, saying it gives "impunity" to murderers and kidnappers. Current President Juan Manuel Santos has promised that justice will be served, but details are not clear.
Still, the guerrillas have been planning for peace, holding a weeklong conference in their jungle stronghold in southern Colombia to share news of what the deal will mean for the fighters as they are asked to lay down their weapons and return to civil society.
The next step will be the official deal signing in the historic coastal city of Cartagena, which will be attended by UN Secretary General Ban Ki-moon and US Secretary of State John Kerry.
Then will come the referendum -- and whatever follows that.
Marquez warned there could still be weeks of truce as the constitution is updated to guarantee the next stage of the peace process, even if some expected peace to be final the day after a "yes" vote in the referendum.
"Here, there is only one winner and that winner is Colombia. That winner also by extension you can say is Latin America. Colombia's peace is the peace of the continent," Marquez said.