Joshua 15 describes the inheritance of the tribe of Judah, outlining the boundaries and listing cities that were allocated to them. Verse 15:44, "Keilah, Achzib, and Mareshah; nine cities with their villages," is simply a part of that list. Let's break down what it means:

Keilah, Achzib, and Mareshah: These are names of specific cities in the territory assigned to Judah. Each city was a populated center.

Nine cities: This indicates that along with the previously mentioned cities (mentioned in the previous verse), the total number of cities in this particular group or region was nine. These are examples of cities in the Shephelah region.

With their villages: This is a crucial detail. The "villages" were smaller settlements dependent on the main cities. They were likely agricultural communities that relied on the city for trade, defense, and administration. This detail highlights that the inheritance wasn't just about the main cities, but also the surrounding areas under their influence.

In essence, the verse is a concise piece of geographical and administrative information. It tells us that Keilah, Achzib, and Mareshah were among a group of nine cities that belonged to the tribe of Judah, and that these cities each controlled and were surrounded by smaller, dependent villages.

Significance:

Historical Context: These listings provide valuable insight into the population distribution and urban development of ancient Canaan.
Territorial Claims: The verse served as a legal record of the land belonging to Judah, important for resolving disputes and maintaining tribal boundaries.
Biblical Narrative: Understanding the geography helps to contextualize the historical events described in the Bible, such as battles, political alliances, and the lives of biblical figures.

So, this verse isn't a complex theological statement, but rather a specific detail within a larger inventory of land and cities. It gives us a glimpse into the structure of society and the organization of territory in ancient Israel.