Charles Ellicott Commentary Numbers 14:37

"even those men that did bring up an evil report of the land, died by the plague before Jehovah." — Numbers 14:37 (ASV)

By the plague— The word maggephah, which is here rendered plague, denotes a stroke. In Exodus 9:14 it is used of the ten plagues of Egypt. In Numbers 16:48-49, it is used of the plague which broke out after the insurrection of Korah, Dathan, and Abiram, and in Numbers 25:9-18 of that which broke out after the Israelites had joined in the idolatrous and lascivious rites of the Moabites and Midianites. In 1 Samuel 4:17, 2 Samuel 17:9, and 2 Samuel 18:7, it is used of destruction by the sword. It appears to denote here sudden death, inflicted by the immediate visitation of the Lord.