Albert Barnes Commentary 1 Kings 21:8

"So she wrote letters in Ahab`s name, and sealed them with his seal, and sent the letters unto the elders and to the nobles that were in his city, [and] that dwelt with Naboth." — 1 Kings 21:8 (ASV)

Seal - The seal is a very ancient invention. Judah’s signet and Pharaoh’s signet-ring are mentioned in Genesis 38:18 and 41:42. Signets of Egyptian kings have been found that date to around 2000 B.C. Sennacherib’s signet, and an impression of Sargon’s, still exist. There is no doubt that in the East, from a very remote antiquity, kings had seals and attached them to all documents they issued under their authority (8:8). The Hebrew method of sealing seems to have been to attach a lump of clay to the document and impress the seal upon it (Job 38:14).

His city - That is, Jezreel (1 Kings 21:1). The way it is mentioned here, and in 1 Kings 21:11, seems to imply that this was not the city from which Jezebel wrote. The court was evidently residing in Samaria at this time (1 Kings 20:43). Ahab may have either met Naboth there or gone down (compare 1 Kings 21:16) to Jezreel to make his request, and then returned to Samaria after being refused. The distance is no more than seven miles.