Sh'mu'el Alef (1 Sa) 3:9-10

So ‘Eli said to Sh’mu’el, “Go, and lie down. If you are called again, say, ‘Speak, ADONAI; your servant is listening.’ Sh’mu’el went and lay down in his place. ADONAI came and stood, then spoke as at the other times: “Sh’mu’el! Sh’mu’el!” Then Sh’mu’el said, “Speak; your servant is listening.”