Azariah — Two sons called by the same name, though doubtless distinguished by some additional title: which is not mentioned here, because it did not concern succeeding ages to know it. Of Israel — So he is called either, Because he was so by right: or Because he was king not only of Judah and Benjamin, but of a great number of Israelites, who had come and settled in his kingdom.
Related Commentaries of 2 Chronicles 21:2
2 Chronicles 21:2
2 And he had brethren the sons of Jehoshaphat, Azariah, and Jehiel, and Zechariah, and Azariah, and Michael, and Shephatiah: all these were the sons of Jehoshaphat king of Israel.