1 Samuel 3:1

"The boy Samuel ministered before the Lord under Eli. In those days the word of the Lord was rare; there were not many visions." NIV translation

Samuel was probably a teenager at this point as he continued to serve in the Tent of Meeting. We see that the Lord had not been speaking to the priests through visions because of the fact that they were corrupt. They had basically chosen to ignore the word of the Lord and so He stopped talking to them for a time.

1 Samuel 3:2 & 3

"One night Eli, whose eyes were becoming so weak that he could barely see, was lying down in his usual place. The lamp of God had not yet gone out, and Samuel was lying down in the house of the Lord, where the ark of God was." NIV translation

In the early morning, Samuel was lying down by the ark of God. The lamp of God refers to the golden lampstand which stood opposite the table of the bread of Presence. The lamp was filled in the evening and would usually die down and go out at dawn. Eli was near but his vision was getting so bad that he could not see much of what was about to happen.

1 Samuel 3:4 & 5

"Then the Lord called Samuel. Samuel answered, 'Here I am.' And he ran to Eli and said, 'Here I am; you called me.' But Eli said, 'I did not call; go back and lie down.' So he went and lay down." NIV translation

When the Lord called to Samuel, the boy did not recognize that it was God. Instead, he ran to see what Eli needed. We also see that Eli did not immediately recognize that God was calling Samuel. In this we see that Samuel was not yet a child of God and Eli had gotten used to serving God without any input from Him.

The same is true in much of Christianity today as the body has been made to be like a business and ran by managers instead of ministers.