Charles Ellicott Commentary Deuteronomy 7:15

"And Jehovah will take away from thee all sickness; and none of the evil diseases of Egypt, which thou knowest, will he put upon thee, but will lay them upon all them that hate thee." — Deuteronomy 7:15 (ASV)

Evil diseases. —The word for diseases used here is found only in Deuteronomy . It must not be forgotten that the law of Moses was in many of its details a sanitary quite as much as a moral code. Some of the associations of this word and the root from which it is derived would seem to point to those “languors” and “infirmities” which arise from neglect and violation of the laws of God, both moral and physical.