Out of grace toward you, Arjuna, I showed you this supreme form through my own yogic power: radiant, universal, infinite, primal, which no one but you has seen before.
Explanation
Arjuna, terrified by the cosmic form, has just asked Krishna to take back his familiar shape, and Krishna begins his reply by reassuring him. He says the vision was a gift of his grace, shown through his own divine power (ātma-yoga, his yogic power or self-mastery). He stresses that it was his radiant, infinite, primal form, and that no one else had ever seen it before.