Joshua 16:3
And goeth down westward to the coast of Japhleti, unto the coast of Beth-horon the nether, and to Gezer: and the goings out thereof are at the sea. And goeth down westward to the coast of Japhleti, unto the coast of Beth-horon the nether, and to Gezer: and the goings out thereof are at the sea.
The line runs westward to the coast, passing the border of Japhleti, continuing to the border of lower Beth-horon and to Gezer, with its outgoings at the sea. It belongs to the geographical record describing the boundaries of the land allotted to the tribes, and marks in particular the boundary of Ephraim's inheritance. That boundary stands within the division and settling of the Promised Land among the tribes.
It stands in the account of the conquering of the Canaanites and the division of the land among Israel, which comes after the sin of Achan and its consequences. The surrounding section also shows Israel's lack of faith and slowness, ending with the assurance that God did all He had promised and none of His good word failed.