Esther 8:10

8:10 Mordecai wrote in the name of King Ahasuerus and sealed it with the king’s signet ring. He then sent letters by couriers on horses, who rode royal horses that were very swift.

Esther 8:14

8:14 The couriers who were riding the royal horses went forth with the king’s edict without delay. And the law was presented in Susa the citadel as well.