Verse 2: That they (Ex. 15:14-16; Deut. 11:25) feared greatly, because Gibeon was a great city, as one of the royal cities (Heb. cities of the kingdom), and because it was greater than Ai, and all the men thereof were mighty.
[He feared] Hebrew: they feared, namely, the King and his people (Vatablus, Masius). It is plural, because in the word King the citizens are also metonymically contained (Masius). Or, he and the other Kings, verse 3 (Piscator, Masius).
They feared, that is, he and his people, the king being spoken of verse 1, as a public person representing all his people. Or, he and the following kings, verse 3. But this fear is mentioned, verse 2, as the cause why he sent to those kings.
[And one of the royal cities, כְּאַחַ֖ת עָרֵ֣י הַמַּמְלָכָ֑ה] As one of the cities of the kingdom (Montanus, Drusius), or, of kingdoms (Jonathan), from among the cities royal, or regal (Vatablus, Masius, Drusius, Piscator, Junius and Tremellius), that is, in which is a residence of the king (Vatablus, similarly Masius). It was one of the principal cities of the kingdom of the Canaanites (Lapide). But it was not one kingdom, but many, verse 3 (Piscator). Equally as great as whatever other of the cities of the kingdom (Syriac, Arabic). From the particle כ/as they gather that Gibeon was not a royal city (and there is no mention anywhere of a King of the Gibeonites), but was the equal of such. But to others the כ/as does not signify similitude, but the truth of the matter, as in John 1:14; Philippians 2:7 (Bonfrerius).
As one of the royal cities; either, 1. Really a royal city, the Hebrew particle כ/caph oft signifying the truth of a thing, as Hosea 4:4; 5:10, and oft elsewhere. Or, 2. Equal to one of the royal cities, though it had no king, but seems to be governed aristocratically by their elders, Joshua 9:11.
 Hebrew: וַיִּֽירְא֣וּ מְאֹ֔ד כִּ֣י עִ֤יר גְּדוֹלָה֙ גִּבְע֔וֹן כְּאַחַ֖ת עָרֵ֣י הַמַּמְלָכָ֑ה וְכִ֙י הִ֤יא גְדוֹלָה֙ מִן־הָעַ֔י וְכָל־אֲנָשֶׁ֖יהָ גִּבֹּרִֽים׃
 Hebrew: עָרֵ֣י הַמַּמְלָכָ֑ה.
 Hebrew: וַיִּירְאוּ.
 Hosea 4:4: “Yet let no man strive, nor reprove another: for thy people are as they that strive (כִּמְרִיבֵי) with the priest.”
 Hosea 5:10: “The princes of Judah were like them that remove (כְּמַסִּיגֵי) the bound: therefore I will pour out my wrath upon them like water.”