Bible Notes Online - Joshua 21 - ESV
Commentary

v1-3: Cities were set apart for the Levites, throughout Israel, both east and west of the Jordan; fulfilling Gen 49.7.

v4-8: Judah, Simeon, and Benjamin, gave 13 cities to the family of Aaron, the Kohathites, listed v9-19. Included here was Hebron a city of refuge (v13).

Ephraim, Dan, and half the tribe of Manasseh, gave 10 cities for the rest of the Kohathites, listed in v20-26. Included here was Shechem (c21), a city of refuge. Elkanah, father of Samuel, was of the line of Kohath (1 Chr 6.33-38); he lived in Ephraim (1 Sam 1.1); thus indicating the accuracy and consistency of Scripture.

Issachar, Asher, Naphtali, and half the tribe of Manasseh, gave 13 cities for the Gershonites, listed in v27-33. Included here were Golan (v27), and Kedesh (v32), cities of refuge.

Zebulun, Reuben, and Gad, gave 12 cities for the Merarites, listed in v34-40. Included here were Bezer (v36), and Ramoth (v38), cities of refuge.

The presence of cities of refuge east of the Jordan was a sign of God's grace towards His people; for those tribes had chosen not to enter the promised land.

v11-12: Caleb's city, Hebron, was given to the priests; he kept the villages and fields belonging to the city.

v43-45: Summarising the position so far; Israel had occupied the bulk of Canaan, although some Canaanites dwelt in the land still (see Judg 1-2).