“And Solomon reigned over all kingdoms from the river unto the land of the Philistines, and unto the border of Egypt: they brought presents, and served Solomon all the days of his life.”
King James Version (KJV)
4:21 The river - Euphrates: for so far David, having conqueredthe Syrians, extended his empire, which Solomon also maintained inthat extent. And so God's promise concerning the giving the whole land, asfar as Euphrates, to the Israelites, was fulfilled. And, if theIsraelites had multiplied so much that the land of Canaan would notsuffice them, having God's grant of all the land as far as Euphrates,they might have seized upon it whensoever occasion required. The landof the Philistines - Which is to be understood inclusively; for thePhilistines were within Solomon's dominion. The border ofEgypt - Unto the river Sihor, which was the border between Egyptand Canaan. And served - By tribute, or other ways, as he neededand required.