1 Samuel 3:21

And the child Samuel ministered unto the LORD before Eli. And the word of the LORD was precious in those days; there was no open vision.

And it came to pass at that time, when Eli was laid down in his place, and his eyes began to wax dim, that he could not see;

And ere the lamp of God went out in the temple of the LORD, where the ark of God was, and Samuel was laid down to sleep;

That the LORD called Samuel: and he answered, Here am I.