Then the king Ahasuerus answered and said unto Esther the queen, Who is he, and where is he, that durst presume in his heart to do so?

And king Assuerus answered and said: Who is this, and of what power, that he should do these things?

And king Ahasuerus spoke and said to Esther the queen, Who is he, and where is he that has filled his heart to do so?

And the king Ahasuerus saith, yea, he saith to Esther the queen, 'Who is he, this one? and where is this one?, he whose heart hath filled him to do so?'

Then King Ahasuerus said to Esther the queen, Who is he and where is he who has had this evil thought in his heart?

Who is he, and where is he - There is a wonderful abruptness and confusion in the original words, highly expressive of the state of mind in which the king then was: מי הוא זה ואי זה הוא אשר מלאו לבו לעשות כן mi hu zeh veey zeh hu asher melao libbo laasoth ken.
"Who? He? This one? And where? This one? He? Who hath filled his heart to do thus?" He was at once struck with the horrible nature of a conspiracy so cruel and diabolic.

Then the King Ahasuerus answered and said unto Esther the queen,.... The words in the original text lie thus, "and the King Ahasuerus said, and he said to Esther the queen"; which doubling of the word does not signify, as Jarchi suggests, that before he spoke to her by a messenger, or middle person, but, now he knew she was of a royal family, he spoke to her himself; but it is expressive of the ruffle of his mind, and the wrath and fury he was in, that he said it again and again, with a stern countenance and great vehemence of speech:
who is he? and where is he? who is the man? and where does he live?
that durst presume in his heart to do so; that has boldness, impudence, and courage enough to perpetrate so vile an action: or "that has filled his heart" (i); the devil no doubt filled his heart to do it, see Acts 5:3, but the king had either forgot the decree he had granted, and the countenance he had given him to execute it; or, if he remembered it, he was now enraged that he should be drawn in to such an action by him; and perhaps till now was ignorant of Esther's descent, and knew not that she would be involved in the decree.
(i) "qui replevit cor suum", Drusius; "implevit", De Dieu.

The king, whose indignation was excited by what he had just heard, asks with an agitation, shown by the repetition of the ויּאמר: "Who is he, and where is he, whose heart hath filled him (whom his heart hath filled) to do so?" Evil thoughts proceed from the heart, and fill the man, and impel him to evil deeds: Isaiah 44:20; Ecclesiastes 8:11; Matthew 15:19.

Who, &c. - The expressions are short and doubled, as proceeding from a discomposed and enraged mind. Durst - That is, to circumvent me, and procure a decree, whereby not only my estate should be so much impaired, and so many of my innocent subjects destroyed, but my queen also involved in the same destruction. We sometimes startle at that evil, which we ourselves are chargeable with. Ahasuerus is amazed at that wickedness, which he himself was guilty of. For he consented to the bloody edict. So that Esther might have said, Thou art the man!