Numbers 16:28-30

28Then Moses said, “This is how you will know that the Lord has sent me to do all these works, for I have not done them of my own will.

29If these men die a natural death, or if they share the fate of all men, then the Lord has not sent me.

30But if the Lord does something entirely new, and the earth opens its mouth and swallows them up along with all that they have, and they go down alive to the grave, then you will know that these men have despised the Lord!”