Kill Drona, Bheeshma, Jayadratha, Karna and the other brave fighters. Be not pained or troubled. They are (already) slain by Me (the Supreme). Fight, and win over the adversaries in the battle.
Krishna becomes more specific and firm. He singles out the great heroes, exhorting Arjuna to kill them, stating that they are already slain by the Supreme. As is the ceaseless revolution of earth, so the event of Kurukshetra battle also is a handiwork of Time. Krishna asks Arjuna to be impersonal in his vision.
Arjuna has to fight and kill a number of others also in the enemy camps. Krishna says all of them are out to kill his army. Arjuna should forestall their attempt. To strike an enemy, no hurt or doubt is to be fostered. It is part of the benign duty of the kshatriyas to the subjects.