Numbers 14:33-34

33Your sons shall be wanderers and shepherds in the wilderness for forty years, and they will suffer for your unfaithfulness (spiritual infidelity), until your corpses are consumed in the wilderness.

34According to the number of days in which you spied out the land [of Canaan], forty days, for each day, you shall bear and suffer a year for your sins and guilt, for forty years, and you shall know My displeasure [the revoking of My promise and My estrangement because of your sin].