1 Samuel 3:7-11

Now Samuel did not yet know Jehovah, neither was the word of Jehovah yet revealed unto him. And Jehovah called Samuel again the third time. And he arose and went to Eli, and said, Here am I; for thou calledst me. And Eli perceived that Jehovah had called the child. Therefore Eli said unto Samuel, Go, lie down: and it shall be, if he call thee, that thou shalt say, Speak, Jehovah; for thy servant heareth. So Samuel went and lay down in his place. And Jehovah came, and stood, and called as at other times, Samuel, Samuel. Then Samuel said, Speak; for thy servant heareth. And Jehovah said to Samuel, Behold, I will do a thing in Israel, at which both the ears of every one that heareth it shall tingle.