Charles Spurgeon Commentary 1 Samuel 3:7-8

"Now Samuel did not yet know Jehovah, neither was the word of Jehovah yet revealed unto him. And Jehovah called Samuel again the third time. And he arose and went to Eli, and said, Here am I; for thou calledst me. And Eli perceived that Jehovah had called the child." — 1 Samuel 3:7-8 (ASV)

Neither was the word of the LORD yet revealed unto him. And the LORD called Samuel again the third time.

We do not blame Samuel, for he was only a child, and spiritual understanding had not yet fully come to him; but what shall I say of some to whom God has spoken for years until their hair is gray, and yet they have not understood the voice of the Lord even to this hour?

I pray God that he may call them yet again. The Lord did not disdain to call Samuel four times, for when he means effectually to call, if one call is not sufficient, he will call again and again and again: The Lord called Samuel again the third time.