"In attacking Malala, the terrorist have failed to grasp that she is not only an individual, but an icon of courage and hope who vindicates the great sacrifices that the people of Swat and the nation gave, for wresting the valley from the scourge of terrorism," Kayani said.
He vowed the military would not bow to terrorists like those who shot the young activist.
"We will fight, regardless of the cost we will prevail," he said.
He also visited the hospital to get a first-hand account of her condition, the statement said.
Malala is admired across Pakistan for exposing the Taliban's atrocities and advocating for girls' education in the face of religious extremism.
Image: In this handout photograph released by the Pakistan's Inter Services Public Relations (ISPR) office on October 9, 2012, Pakistani army doctors give treatment to injured Malala Yousafzai, 14, at an army hospital following an attack by gunmen in Peshawar on October 9, 2012. (Image credit: AFP)