Judges 3:2

if only to teach warfare to the subsequent generations of Israel, especially to those who had not known it formerly:

Berean Standard Bible
Other translations

King James Version

Only that the generations of the children of Israel might know, to teach them war, at the least such as before knew nothing thereof;

World English Bible

only that the generations of the children of Israel might know, to teach them war, at least those who knew nothing of it before:

American Standard Version

only that the generations of the children of Israel might know, to teach them war, at the least such as beforetime knew nothing thereof:

Geneva Bible 1599

Only to make the generations of the children of Israel to know, and to teach them warre, which doutles their predecessors knew not)

Darby Translation

only that the generations of the children of Israel might know war by learning it, at the least those who before had known nothing thereof:

Young's Literal Translation

(only for the sake of the generations of the sons of Israel's knowing, to teach them war, only those who formerly have not known them) —

Bible in Basic English

Only because of the generations of the children of Israel, for the purpose of teaching them war — only those who up till then had no experience of it;

In context

1These are the nations that the LORD left to test all the Israelites who had not known any of the wars in Canaan,

3the five rulers of the Philistines, all the Canaanites, the Sidonians, and the Hivites who lived in the mountains of Lebanon from Mount Baal-hermon to Lebo-hamath.

Read Judges 3