In the reign of Sargon (722 BC - 715 BC), the successor of Shalmaneser, an Assyrian invasion of Egypt took place. Its success is here foretold; and hence a party among the Jews are warned of the folly of their "expectation" of aid from Egypt or Ethiopia. At a later period (Isaiah 18:1-7), when Tirhakah of Ethiopia was their ally, the Ethiopians are treated as friends, to whom God announces the overthrow of the common Assyrian foe, Sennacherib. Egypt and Ethiopia in this chapter (Isaiah 20:3-4) are represented as allied together, the result, no doubt, of fear of the common foe. Previously they had been at strife (Isaiah 19:2), and the Ethiopian king had, just before Sethos' usurpation, withdrawn from occupation of part of Lower Egypt. Hence, "Egypt" is mentioned alone in Isaiah 19:1-25, which refers to a somewhat earlier stage of the same event-a delicate mark of truth. Sargon seems to have been the king who finished the capture of Samaria, which Shalmaneser began.
The alliance of Hoshea with So, or Sabacho II, of Ethiopia, and his refusal to pay the usual tribute, provoked Shalmaneser to the invasion. On clay cylindrical seals, found in Sennacherib's palace at Kouyunjik, the name of Sabacho is deciphered. The two seals are thought, from the inscriptions, to have been attached to the treaty of peace between Egypt and Assyria, which resulted from the invasion of Egypt by Sargon, described in this chapter. 2 Kings 17:10 curiously confirms the view derived from Assyrian inscriptions, that though Shalmaneser began, Sargon finished the conquest of Samaria: 'they took it' (Samaria). Compare 2 Kings 17:4-6, "came up Shalmaneser ... Then the king of Assyria went up." In Sargon's palace at Khorsabad the inscriptions state that 27,280 Israelites were led captive by the founder of the palace. While Shalmaneser was engaged in the siege of Samaria, Sargon probably usurped the supreme power and destroyed him.
The siege began in 723 BC, and ended in 721 BC-the first year of Sargon's reign. Hence, arises the paucity of inscriptions of the two predecessors of Sargon, Tiglath-pileser and Shalmaneser. The usurper destroyed them, just as Tiglath-pileser destroyed those of Pul (Sardanapalus), the last of the old line of Ninus. The names of his father and grandfather, which have been deciphered in the palace of his son Sennacherib, do not appear in the list of Assyrian kings, which confirms the view that he was a satrap who usurped the throne. He was so able a general that Hezekiah made no attempt to shake off the tribute until the reign of Sennacherib; hence, Judah was not invaded now, as the land of the Philistines and Egypt were. After conquering Israel, he sent his general, Tartan, to attack the Philistine cities, "Ashdod," etc., preliminary to his invasion of Egypt and Ethiopia; because the line of march to Egypt lay along the southwest coast of Palestine. The inscriptions confirm the prophecy: they tell us he received tribute from a Pharaoh of "Egypt," besides destroying in part the Ethiopian 'No-Ammon,' or Thebes (Nahum 3:8); also that he warred with the kings of "Ashdod," Gaza, etc., in harmony with Isaiah here. A memorial tablet of him is found in Cyprus also, showing that he extended his arms to that island. His reign was six or seven years in duration-722 BC - 715 BC (G.V. Smith.)
Tartan - probably the same general as was sent by Sennacherib against Hezekiah (2 Kings 18:17). Gesenius takes "Tartan" as a title.
Came unto Ashdod - called by the Greeks Azotus (Acts 8:40); on the Mediterranean: one of the 'five' cities of the Philistines. The taking of it was a necessary preliminary to the invasion of Egypt, to which it was the key in that quarter, the Philistines being allies of Egypt. So strongly did the Assyrians fortify it that it stood a twenty-nine years' siege, when it was retaken by the Egyptian Psammitichus.
(When Sargon the king of Assyria sent him.) Sargon himself remained behind, engaged with the Phoenician cities, or else led the main force more directly into Egypt out of Judah (G.V. Smith).