1 Samuel 12:16-18

Now therefore stand and see this great thing, which the LORD will do before your eyes. Is it not wheat harvest to day? I will call unto the LORD, and he shall send thunder and rain; that ye may perceive and see that your wickedness is great, which ye have done in the sight of the LORD, in asking you a king. So Samuel called unto the LORD; and the LORD sent thunder and rain that day: and all the people greatly feared the LORD and Samuel.