Mbh 6.108.5a

“Bhishma said, ‘That, O son of Pandu, is true, which thou sayest, O thou of mighty arms. When with weapons and my large bow in hand I contend carefully in battle, I am incapable of being defeated by the very gods and the Asuras with Indra at their head. If, however, I lay aside my weapons, even these car-warriors can slay me. One that hath thrown away his weapons, one that hath fallen down, one whose armour hath slipped off, one whose standard is down, one who is flying away, one who is frightened, one who says--“I am thine”--one who is a female, one who beareth the name of a female, one no longer capable of taking care of one’s self, one who hath only a single son, or one who is a vulgar fellows,--with these I do not like to battle. Hear also, O king, about my resolve formed before. Beholding any inauspicious omen I would never fight. That mighty car-warrior, the son of Drupada, O king, whom thou hast in thy army, who is known by the name of Sikhandin, who is wrathful in battle, brave, and ever victorious, was a female before but subsequently obtained manhood. How all this took place, ye all know it truly. Brave in battle and clad in mail, let Arjuna, keeping Sikhandin before him, attack me with his sharp shafts. When that inauspicious omen will be there, especially in the form of one that was a female before, I will never seek, though armed with bow and arrow, to strike him. Obtaining that opportunity, let Dhananjaya the son of Pandu quickly pierce me on every side with his shafts, O bull of Bharata’s race. Except the highly blessed Krishna, and Dhananjaya the son of Pandu, I do not behold the person in the three worlds who is able to slay me while exerting myself in battle. Let Vibhatsu, therefore, armed with weapons, struggling carefully in battle, with his excellent bow in hand, placing (Sikhandin or) something else before, throw me down (from my car). Then the victory will be certain.