The Emir of Kano, Muhammad Sanusi, said residents should "acquire what they need" to protect themselves.
One of northern Nigeria's most influential Muslim leaders has called on people to defend themselves against attacks by the Boko Haram militant Islamist group.
The Chat212 FM, in Nigeria, says such an intervention is very unusual.
A police spokesman said the Emir's comments were a "call for anarchy" and should not be acted on.
The emir, who until earlier this year was governor of Nigeria's central bank, normally stays silent on political matters.
He made the comments at a prayer meeting, following several further attacks in recent days blamed on Boko Haram.
Jihadists from the group continue to cause havoc in parts of north-east Nigeria, capturing towns and villages where they have been imposing their own strict interpretation of Islamic law.
Primary schools in one of the worst-affected areas have begun reopening after being closed for the past eight months.
Boko Haram, which means "Western education is forbidden", often attacks educational establishments.
Some of the schools are to be protected by self-defence groups.
The emir, who strongly criticised the government when he was a banker, said people should not be afraid of the militants and should prepare to defend themselves.
"These terrorists slaughter our boys and abduct our girls to force them into slavery," he said.
"People should not sit idle and say prayer is the only solution. People should be made aware of the importance of being in a state of preparedness and make sure they acquire what they need to protect themselves. We should be ready to give our lives."
The emir said residents should not wait for help from the military. There have been numerous reports of soldiers deserting, saying they are not as well equipped as the militants.
Police spokesman Emmanuel Ojukwu said: "Any call for citizens to arm themselves is a call for anarchy and lawlessness. And this is not allowed under our laws. Such a call should be disregarded. The police [force] is living up to its duty to protect lives and property."