Ramayana
त्रिधाभूतं करिष्यामि ह्यात्मानं सुरसत्तमाः । तेन वृत्रं सहस्राक्षो वधिष्यति न संशयः ॥ 7-85-6 ॥
"I shall make myself threefold, O best of the gods; by that the thousand-eyed one shall slay Vritra, of this there is no doubt."
english translation