President Obama remembered a personal hero Tuesday -- a man whose example "woke me up to my responsibilities" -- before an adoring and soaked stadium audience on the outskirts of Johannesburg.

In his words memorializing late South African president Nelson Mandela, Obama delivered a celebration and a scolding, a eulogy mixing past and present that, in its acknowledgment of failure, its emphasis on persistence and its call for cooperation, reflected this challenging moment in Obama's presidency.

The parallels he drew were unmistakable, as was the lilting, sometimes angry delivery he used to invoke them.