"Mandate" and "edict" are synonyms for a law that King Creon is soon arriving to promulgate. This formal declaration of a law emphasizes the power of a king's speech, which will be challenged later by the speech of a young girl. Keep in mind that this is a play where all the conflicts and power shifts are developed through dialogue rather than action.
Such is the edict (if report speak true)
Of Creon, our most noble Creon, aimed
At thee and me, aye me too; and anon
He will be here to promulgate, for such
As have not heard, his mandate;
Ismene reminds Antigone of their father's fate, because she does not want that to happen to them. But as the daughters/sisters of a man who'd killed his father and married his mother, they already carry some of the abhorred dishonor of Oedipus's life and death.
Bethink thee, sister, of our father's fate, Abhorred, dishonored, self-convinced of sin,
Blinded, himself his executioner.
Although Antigone starts her speech by saying she will not try to urge Ismene anymore, these lines about sweetly abiding with brothers who will love and praise her forever are meant to both shame Ismene and let her know what she'd be missing out on.
How sweet to die in such employ, to rest,—
Sister and brother linked in love's embrace—
A sinless sinner, banned awhile on earth,
But by the dead commended; and with them
I shall abide for ever.
But for the miscreant exile who returned
Minded in flames and ashes to blot out
His father's city and his father's gods,
And glut his vengeance with his kinsmen's blood,
Or drag them captive at his chariot wheels—
For Polyneices 'tis ordained that none
Shall give him burial or make mourn for him,
Another definition of "prevail" is "use persuasion successfully"--on the surface, the guard is simply saying that his forward voice prevailed over his cowardly silence, but throughout his speech, he is hoping that he could persuade Creon not to kill him for bringing him bad news.
But in the end the forward voice prevailed,
To face thee. I will speak though I say nothing.
For plucking courage from despair methought,
'Let the worst hap, thou canst but meet thy fate.'
Is it not arrant folly to pretend
That gods would have a thought for this dead man?
Did they forsooth award him special grace,
And as some benefactor bury him,
Who came to fire their hallowed sanctuaries,
To sack their shrines, to desolate their land,
And scout their ordinances? Or perchance
The gods bestow their favors on the bad.
made of or resembling brass (as in color or hardness)
Another definition of "brazen" is "face with defiance or impudence"--while the example sentence is using "brazen" as an adjective to describe the urn, the verb "brazen" could be used to describe how Antigone is deliberately and openly disobeying Creon's mandate.
Anon she gathered handfuls of dry dust,
Then, holding high a well-wrought brazen urn,
Thrice on the dead she poured a lustral stream.
This is an odd view to declare to one's king. But the guard, in presenting Antigone as a law breaker, is both serving the king and saving himself from being accused. In risking her own life to serve her brother, Antigone is showing that she deems the guard's view to be wrong.
Take it all in all, I deem
A man's first duty is to serve himself.
But this proud girl, in insolence well-schooled,
First overstepped the established law, and then—
A second and worse act of insolence—
She boasts and glories in her wickedness.
Now if she thus can flout authority
Unpunished, I am woman, she the man.
to cause to separate and go in different directions
Notice how Creon is personifying Anarchy with the feminine pronoun "She"--he is trying to equate Antigone's one act of disobedience with the verbs "dissipate," "ruin," and "overthrow". This logic does not work because the kingdom actually sides with Antigone and because Creon himself is creating anarchy by going against the laws of the gods.
What evils are not wrought by Anarchy!
She ruins States, and overthrows the home,
She dissipates and routs the embattled host;
While discipline preserves the ordered ranks.
Although Haemon arrives too late to succor Antigone, her questions suggest that she did not really believe that she would die for her act. In addition to having divine law on her side, she is the niece of Creon and the intended bride of Creon's son. Antigone's royal background enabled her to argue with Creon, which threatened Creon's sense of self and power, and leads to her needing succor.
What ordinance of heaven have I transgressed?
Hereafter can I look to any god
For succor, call on any man for help?
seize and take control without authority and possibly with force; take as one's right or possession
For that thou hast entombed a living soul,
And sent below a denizen of earth,
And wronged the nether gods by leaving here
A corpse unlaved, unwept, unsepulchered.
Herein thou hast no part, nor e'en the gods
In heaven; and thou usurp'st a power not thine.
He had saved this land
Of Cadmus from our enemies and attained
A monarch's powers and ruled the state supreme,
While a right noble issue crowned his bliss.
Now all is gone and wasted, for a life
Without life's joys I count a living death.
When the King saw him, with a terrible groan
He moved towards him, crying, "O my son
What hast thou done? What ailed thee? What mischance
Has reft thee of thy reason? O come forth,
Come forth, my son; thy father supplicates."
The tumult of the Queen's heart does lead to her fall. "Fell" is actually used as an adjective here that means "disposed to inflict pain or suffering"--to ease the tumult of her heart from the loss of her son, the Queen chooses to kill herself. This design is fell because she inflicts pain on herself and causes the King and the rest of the kingdom to suffer another loss.
Well, let us to the house and solve our doubts,
Whether the tumult of her heart conceals
Some fell design.
Chastisement often takes the form of a verbal punishment, but that was not enough for Creon to see the error of his ways. Although chastised by Antigone, Haemon, and Tiresias, Creon did not recognize that he was just a "worthless wretch"--not until the gods smacked him down by taking away his son and wife.
Swelling words of high-flown might
Mightily the gods do smite. Chastisement for errors past
Wisdom brings to age at last.