Judges 3:4

4 They were left to test the Israelites to see whether they would obey the LORD’s commands, which he had given their ancestors through Moses.

Read Judges 3:4 Using Other Translations

And they were to prove Israel by them, to know whether they would hearken unto the commandments of the LORD, which he commanded their fathers by the hand of Moses.
They were for the testing of Israel, to know whether Israel would obey the commandments of the LORD, which he commanded their fathers by the hand of Moses.
These people were left to test the Israelites—to see whether they would obey the commands the LORD had given to their ancestors through Moses.

What does Judges 3:4 mean?

John Gill's Exposition of the Bible
Judges 3:4

And they were to prove Israel by them
They were left in the land, as to inure them to war, and try their courage, so to prove their faithfulness to God:

to know whether they would hearken to the commandments, of the Lord,
which he commanded their fathers by the hand of Moses;
even all the commandments of the Lord delivered to them by Moses, moral, civil, and ceremonial, and particularly those that concerned the destruction of the Canaanites, their altars, and their idols, ( Deuteronomy 7:1 Deuteronomy 7:5 ) .

California - Do Not Sell My Personal Information  California - CCPA Notice