Comeuppance

Hung on the gallows he built for another

H, by King X to honour was raised,
H, by King X was empowered and praised;
but H was so angry that M wouldn’t bow,
‘Vengeance on all of the Jews’ – his vow.

H had a sizable gallows made,
confidant that the King X he’d persuade
to let him hang M (as his wife was suggesting);
– that night, X was wakeful – instead of him resting,

he asked that the book of his reign they would bring –
they read how a plot on the life of the King
had been heard and reported by M, but that naught
had been done to show praise for assassins caught.

‘What shall be done for the one whom I ought
to honour’, the King asked, and H proudly thought
‘He must mean for me!’ and suggested he dress
that one in a robe, ride a royal king’s horse,

and lead him throughout all the city proclaiming
‘This man is honoured’ – H heard the king naming
M as the man who by H must be led
(not hung on his gallows, but favoured instead!).

When Esther made known the plot H had devised    
to destroy all her people, X’s anger was roused,
– H then fell upon her to plead for his life,
but X, when he thought H assaulting his wife,

grew even more angry – the gallows H made
was used for himself, and a lesson conveyed
that malice and pride, though they hate, will instead
one day bring their schemes down upon their own head!

based on the story of the book of Esther in the Bible (especially 2:19-8:17), when some of the Jews had been allowed to return to their land, but some were still in Persia.
X=Xerxes, M=Mordecai, H=Haman