Esther 1:10
“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,”
KJV
Read in Esther 1Meaning
The timing connects the command that follows with the atmosphere of the drinking feast. The narrator does not need to explain the king's motives in detail; the setting is enough to underline the impulsive character of what comes next.