Now the LORD came and stood and called as at other times, "Samuel! Samuel!" And Samuel answered, "Speak, for Your servant hears."
1 Samuel 3:10
Surrounding context
3:9 Therefore Eli said to Samuel, "Go, lie down; and it shall be, if He calls you, that you must say, "Speak, LORD, for Your servant hears."' So Samuel went and lay down in his place.
3:10 Now the LORD came and stood and called as at other times, "Samuel! Samuel!" And Samuel answered, "Speak, for Your servant hears."
3:11 Then the LORD said to Samuel: "Behold, I will do something in Israel at which both ears of everyone who hears it will tingle.