So the king took his signet ring from his hand and gave it to Haman the Agagite, the son of Hammedatha, the enemy of the Jews.
Haman values himself upon that bold and daring thought, which he fancied well became his great spirit, of destroying all the Jews - an undertaking worthy of its author, and which he promised himself would perpetuate his memory. He doubts not but to find desperate and bloody hands enough to cut all their throats if the king will but give him leave.
Commenting on Esther 3:7-15
And the king took his ring from his hand, and gave it unto Haman, the son of Hammedatha the Agagite, the Jews' enemy. As a token of his affection for him, and a mark of honour to him; with the Persians (w) for a king to give a ring to anyone was a token and bond of the greatest love and friendship imaginable; and it...
the king took his ring from his hand, and gave it unto Haman--There was a seal or signet in the ring. The bestowment of the ring, with the king's name and that of his kingdom engraven on it, was given with much ceremony, and it was equivalent to putting the sign manual to a royal edict.