1 Samuel 3:2, 7, 9

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

Now Samuel did not yet know the LORD, neither was the word of the LORD yet revealed unto him.

Therefore Eli said unto Samuel, Go, lie down: and it shall be, if he call thee, that thou shalt say, Speak, LORD; for thy servant heareth. So Samuel went and lay down in his place.