The posts went - The bearers of the letters were probably the “runners” who formed a portion of the king’s body-guard (2 Kings 10:25 note).
The kings of Assyria - Pul, Tiglath-pileser, and Shalmaneser may all be referred to in this passage (compare the marginal reference and 2 Kings 17:3). The passage by no means implies that the fall of Samaria and final captivity of the Israelites had as yet taken place.