Hazor was one of the largest cities in the country for two thousand years and was one of Solomon's "royal" cities during the first temple period. Its importance stemmed from it being on the trade route to northern kingdoms and close to the border.

Joshua Chapter 11

13 But none of the cities that stood on mounds did Israel burn, except Hazor only; that Joshua burned. 14 And all the spoil of these cities and the cattle, the people of Israel took for their booty; but every man they smote with the edge of the sword, until they had destroyed them, and they did not leave any that breathed.

The Revised Standard Version, (New York: Oxford University Press, Inc.) 1973, 1977.