The anxiety hidden behind the order "Protect the strongest Bishama."
Our army is protected by Bhishma, so it cannot be conquered. Immediately after saying this, Duryodhana ordered the entire army: "Protect Bhishma." This is a seemingly strange order to protect the strongest warrior.
Bishma had sufficient power to protect himself. However, he decided not to fight with Shikhandi. Because Shikhandi was born as a female and later became a male, Bhishma did not consider him a man according to the warrior's code and therefore did not direct his weapons at him.
Duryodhana feared this one thing above all else. He ordered everyone to protect their positions and prevent Shikhandi from appearing before Bhishma.
Because I believe in Bishuma's strength, I am wary of the conditions under which that strength might not work. The anxiety hidden behind those confident words becomes apparent in Chapter 11.
Japanese Translation from the Geeta Press Edition - Chapter 1, Section 11: "Protect Bishma from All Directions."
Chapter 1, Section 11
In all the places, they are situated according to their respective roles. All of you should protect Bhishma alone. || 11 ||
Translation
Therefore, you are to remain in your respective positions on all fronts, and especially protect Bishma from every direction.
Annotative Translation
The great warrior Bishma possessed the power to protect himself.
Duryodhana also knew that fact very well.
However, Bheeshma had declared the following about Shikhandi, the son of Drupada:
Shikandee was born as a female, and later became male due to changes in sex characteristics.
However, because he was born as a woman, Beezma still considered him to be female, and would not face him on the battlefield in accordance with the chivalric code of Kshatriya warriors.
Therefore, Duryodhana had previously inspected the army and explained this danger in detail to Dushasana and other warriors, urging them to be careful.
Once again, moved by that anxiety deep within his heart, Duryodhana orders all of his army's major generals.
Each person should defend their assigned position in combat with all their might.
And during the battle, take special care and vigilance to prevent Sikandee from having an opportunity to appear in front of Bheeshma.
If SIKANDI were to attempt such a thing, it would be necessary to drive him away by force immediately.
If only we could protect Bishma from Shikhandi, there would be nothing else to fear for the Kauravas.
Because, for Bhishma, it was completely easy to defeat all of the Pandava army's Maharathees individually.