1Samuel 3.10
2 And it came to pass one day, when Eli was lying in his chamber (his eyes had begun to darken, and he could not see well), 3 when the lamp of God had not yet gone out, and Samuel was lying in the temple of the Lord, where the ark of God was, 4 that the Lord called Samuel, and he said, Here I am. 5 And he ran to Eli, and said unto him, Here am I; for thou hast called me. But Eli answered him, I have not called; lie down again. And he went and lay down. 6 And the Lord called again, Samuel! And Samuel arose, and went to Eli, and said, Here I am; for thou hast called me. But he answered, I have not called, my son, lie down again. 7 And Samuel knew not yet the Lord, neither was the word of the Lord revealed unto him. 8 And the Lord called Samuel again the third time. And he arose, and went to Eli, and said, Here am I; for thou hast called me. Then Eli understood that the Lord was calling the boy. 9 And Eli said to Samuel, "Go and lie down, and if He calls you, you will say, 'Speak, Lord, for your servant is listening. And Samuel went and lay down in his chamber.
10 Then the Lord came and stood still, and called as on other occasions: Samuel, Samuel! And Samuel answered, Speak; for thy servant heareth.