'Since the Lord wasn't able to bring this people into the land He swore to [give] them, He has slaughtered them in the wilderness.'
Numbers 14:16 In-Context
And they will tell the inhabitants of this land about it. They have already heard that you, LORD, are with these people and that you, LORD, have been seen face to face, that your cloud stays over them, and that you go before them in a pillar of cloud by day and a pillar of fire by night.
If you put all these people to death, leaving none alive, the nations who have heard this report about you will say,
‘The LORD was not able to bring these people into the land he promised them on oath, so he slaughtered them in the wilderness.’
“Now may the Lord’s strength be displayed, just as you have declared:
‘The LORD is slow to anger, abounding in love and forgiving sin and rebellion. Yet he does not leave the guilty unpunished; he punishes the children for the sin of the parents to the third and fourth generation.’