New Revised Standard Version
But the Israelites did not attack them, because the leaders of the congregation had sworn to them by the LORD, the God of Israel. Then all the congregation murmured against the leaders.

Contemporary English Version
But they did not attack the towns, because the Israelite leaders had sworn in the name of the LORD that they would let these people live. The Israelites complained about their leaders' decision not to attack,

New American Bible
but did not attack them, because the leaders of the community had sworn to them by the LORD, the God of Israel. When the entire community grumbled against the leaders,

Douay-Rheims Bible
And they slew them not, because the princes of the multitude had sworn in the name of the Lord, the God of Israel. Then all the common people murmured against the princes.

And they slew them not, because the princes of the multitude had sworn in the name of the Lord, the God of Israel. Then all the common people murmured against the princes.

had sworn

2 Samuel 21:7 And the king spared Miphiboseth the son of Jonathan the son of Saul, because of the oath of the Lord, that had been between David and Jonathan the son of Saul.

Psalm 15:4 In his sight the malignant is brought to nothing: but he glorifieth them that fear the Lord. He that sweareth to his neighbour, and deceiveth not;

Ecclesiastes 5:2,6 Speak not any thing rashly, and let not thy heart be hasty to utter a word before God. For God is in heaven, and thou upon earth: therefore let thy words be few. . . .

Ecclesiastes 9:2 But all things are kept uncertain for the time to come, because all things equally happen to the just and to the wicked, to the good and to the evil, to the clean and to the unclean, to him that offereth victims, and to him that despiseth sacrifices. As the good is, so also is the sinner: as the perjured, so he also that sweareth truth.