Because Jehovah was not able to bring this people into the land which he sware unto them, therefore he hath slain them in the wilderness.

‘Because the LORD was unable to bring this people into the land He swore to give them, He has slaughtered them in the wilderness.’

From Jehovah's want of ability to bring in this people unto the land which He hath sworn to them--He doth slaughter them in the wilderness.

Because Jehovah was not able to bring this people into the land that he had sworn unto them, he has therefore slain them in the wilderness.