Translations
Therefore the LORD left those nations, without driving them out hastily; neither delivered he them into the hand of Joshua.
So YHWH let those nations remain—not driving them out quickly—and He had not given them into the hand of Yehoshua.
So Yahweh allowed those nations to remain. He had chosen not to drive them out swiftly, and He had not handed them over to Joshua.
That is why the LORD had left those nations in place and had not driven them out immediately by delivering them into the hand of Joshua.

