Charles Spurgeon Commentary 1 Samuel 3:6

"And Jehovah called yet again, Samuel. And Samuel arose and went to Eli, and said, Here am I; for thou calledst me. And he answered, I called not, my son; lie down again." — 1 Samuel 3:6 (ASV)

And the LORD called yet again, Samuel. And Samuel arose and went to Eli, and said, Here am I; for you did call me.

He felt sure of it, confident that he had not been mistaken.