Charles Spurgeon Commentary 1 Samuel 3:16-18

"Then Eli called Samuel, and said, Samuel, my son. And he said, Here am I. And he said, What is the thing that [Jehovah] hath spoken unto thee? I pray thee, hide it not from me: God do so to thee, and more also, if thou hide anything from me of all the things that he spake unto thee. And Samuel told him every whit, and hid nothing from him. And he said, It is Jehovah: let him do what seemeth him good." — 1 Samuel 3:16-18 (ASV)

Then Eli called Samuel, and said, Samuel, my son. And he answered, Here am I. And he said, What is the thing that the LORD hath said unto thee? I pray thee hide it not from me: God do so to thee, and more also, if thou hide any thing from me of all the things that he said unto thee. And Samuel told him every whit, and hid nothing from him.

Samuel was obeying the divine command which had not then been given: He that hath my word, let him speak my word faithfully.