1 Samuel 3:7 - Joseph Benson’s Commentary on the Old and New Testaments

Samuel did not yet know the Lord How God was wont to teach and instruct men in his will. Neither was the word of the Lord yet revealed to him He was not acquainted with the way wherein God made himself and his mind known unto the prophets, because he had never spoken to him before. So that he did not know how to distinguish between the voice of God and that of men. And this ignorance of Samuel served God's design, as it gave Eli the fuller assurance of the truth of God's call and message to Samuel.