On the seventh day, when the king was merry with wine, he commanded Mehuman, Biztha, Harbona, Bigtha and Abagtha, Zethar and Carkas, the seven eunuchs who attended him, to bring Queen Vashti before the king, wearing the royal crown, in order to show the peoples and the officials her beauty; for she was fair to behold. But Queen Vashti refused to come at the king's command conveyed by the eunuchs. At this the king was enraged, and his anger burned within him. (NRSV 1:10-12)
On the seventh day, when the heart of the king was merry with wine, he commanded Mehuman, Biztha, Harbona, Bigtha, and Abagtha, Zethar, and Carcas, the seven chamberlains that served in the presence of Ahasuerus the king, to bring Vashti the queen before the king with the crown royal, to shew the people and the princes her beauty: for she was fair to look on. But the queen Vashti refused to come at the king's commandment by his chamberlains: therefore was the king very wroth, and his anger burned in him. (KJV 1:10-12)
The king tries to show off his first queen, Vashti, as though she were a sex-object. When she refuses, this starts the chain of events that leads to Esther becoming the new queen.
Then Memucan said in the presence of the king and the officials, "Not only has Queen Vashti done wrong to the king, but also to all the officials and all the peoples who are in all the provinces of King Ahasuerus. For this deed of the queen will be made known to all women, causing them to look with contempt on their husbands, since they will say, 'King Ahasuerus commanded Queen Vashti to be brought before him, and she did not come.' This very day the noble ladies of Persia and Media who have heard of the queen's behavior will rebel against the king's officials, and there will be no end of contempt and wrath!" (NRSV 1:16-18)
And Memucan answered before the king and the princes, Vashti the queen hath not done wrong to the king only, but also to all the princes, and to all the people that are in all the provinces of the king Ahasuerus. For this deed of the queen shall come abroad unto all women, so that they shall despise their husbands in their eyes, when it shall be reported, The king Ahasuerus commanded Vashti the queen to be brought in before him, but she came not. Likewise shall the ladies of Persia and Media say this day unto all the king's princes, which have heard of the deed of the queen. Thus shall there arise too much contempt and wrath. (KJV 1:16-18)
The king's advisors urge the king to set an example by divorcing Vashti so that everyone's wives will be more obedient. It's a bit of a patriarchal conspiracy.
"If it pleases the king, let a royal order go out from him, and let it be written among the laws of the Persians and the Medes so that it may not be altered, that Vashti is never again to come before King Ahasuerus; and let the king give her royal position to another who is better than she. So when the decree made by the king is proclaimed throughout all his kingdom, vast as it is, all women will give honor to their husbands, high and low alike." This advice pleased the king and the officials, and the king did as Memucan proposed; he sent letters to all the royal provinces, to every province in its own script and to every people in its own language, declaring that every man should be master in his own house. (NRSV 1:19-22).
If it please the king, let there go a royal commandment from him, and let it be written among the laws of the Persians and the Medes, that it be not altered, That Vashti come no more before king Ahasuerus; and let the king give her royal estate unto another that is better than she. And when the king's decree which he shall make shall be published throughout all his empire, (for it is great,) all the wives shall give to their husbands honour, both to great and small. And the saying pleased the king and the princes; and the king did according to the word of Memucan: For he sent letters into all the king's provinces, into every province according to the writing thereof, and to every people after their language, that every man should bear rule in his own house, and that it should be published according to the language of every people. (KJV 1:19-22)
The king's "a man should be the master of his own house" spiel reaches its inevitable conclusion here, when he officially divorces Vashti to set an example.