O tiger’s heart wrapped in a woman’s hide!
How couldst thou drain the lifeblood of the child
To bid the father wipe his eyes withal,
And yet be seen to bear a woman’s face?
(1.4.138–41)

York speaks these famous lines to Margaret, who has captured him and submitted him to cruel mockery. He is particularly incensed by the way she has given him a kerchief soaked in his dead son’s blood, inviting him to try to wipe his tears of grief with the saturated cloth. For a woman who has supposedly gone to war to preserve her own son’s inheritance, it’s ironic that she should be so gleeful about the death of another’s son. York registers this bitter irony in his claim that Margaret is, in fact, not a woman at all, but a tiger. The civil war between the house of York and the house of Lancaster has created the perfect conditions for such monstrosities. And this is not the last time in the play that Margaret will be called unnatural; her martial prowess will lead many to denounce her aberrant masculinity.

Who’s this? O God! It is my father’s face
Whom in this conflict I unwares have killed.
O, heavy times, begetting such events!
From London by the king was I pressed forth;
My father, being the Earl of Warwick’s man,
Came on the part of York, pressed by his master;
And I, who at his hands received my life,
Have by my hands of life bereavèd him.
(2.5.61–68)

During the first major battle between Yorkist and Lancastrian forces, an anonymous soldier goes to loot a corpse, only to find that he’s killed his own father. With these lines he reflects on how this horrific confusion could have come about, and he laments the tragedy that has befallen him. Shortly after this moment, another soldier discovers that he’s killed his own son. From his vantage on a hill overlooking the battlefield, Henry watches on in agony, mourning the horrific violence of civil strife: “let our hearts and eyes, like civil war, / Be blind with tears, and break, o’ercharged with grief” (2.5.77–78).

Ah, simple men, you know not what you swear.
Look as I blow this feather from my face,
And as the air blows it to me again,
Obeying with my wind when I do blow,
And yielding to another when it blows,
Commanded always by the greater gust—
Such is the lightness of you common men.
But do not break your oaths, for of that sin
My mild entreaty shall not make you guilty.
Go where you will, the king shall be commanded;
And be you kings, command, and I’ll obey.
(3.1.82–92)

Henry addresses these lines to the two gamekeepers who arrest him near the Scottish border. The men claim to have sworn a new oath of loyalty to King Edward IV, effectively nullifying their previous vow to Henry and thereby empowering them to take him captive. Here, Henry registers how the civil war has led to a profoundly unstable situation where allegiance is as fickle as a feather blowing in the wind. What results is an unnatural, topsy-turvy world where commoners give the orders and kings obey.