“Lack may be a clear indication of slack.”
(1) And the whole congregation of the children of Israel assembled together at Shiloh, and set up the tabernacle of the congregation there. And the land was subdued before them.
(2) And there remained among the children of Israel seven tribes, which had not yet received their inheritance.
(3) And Joshua said unto the children of Israel, How long are ye slack to go to possess the land, which the LORD God of your fathers hath given you?
The individual tribes were responsible for completing the task of conquering their territory. However, seven tribes had not yet done their jobs. Their areas had not even been surveyed (“describe,” Joshua 18:4). This slackness led to their not possessing land. Says Keil & Delitszch:
“…for the reasons explained in Joshua 14:1, these tribes showed themselves “slack to go to possess the land which the Lord had given them,” i.e., not merely to conquer it, but to have it divided by lot, and to enter in and take possession.”Keil & Delitszch, Joshua 18:2-10, e-sword, ver. 11.1.
Read the rest of Joshua 18 and see how they followed through. You can have what God has promised you when you take the steps necessary to receive it.