1 Samuel 3:9-11

So Eli said to Samuel, “Go, lie down, and it shall be that if He calls you, you shall say, ‘Speak, LORD, for Your servant is listening.’ ” So Samuel went and lay down in his place. Then the LORD came and stood and called as at the previous times, “Samuel! Samuel!” Then Samuel answered, “Speak, for Your servant is listening.” The LORD said to Samuel, “Behold, I am about to do a thing in Israel at which both ears of everyone who hears it will ring.