A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
1 Kings (1 Samuel) 3:1
sa1 3:1THE LORD APPEARS TO SAMUEL IN A VISION. (Sa1 3:1-10)
the child Samuel ministered unto the Lord before Eli--His ministry consisted, of course, of such duties in or about the sanctuary as were suited to his age, which is supposed now to have been about twelve years. Whether the office had been specially assigned him, or it arose from the interest inspired by the story of his birth, Eli kept him as his immediate attendant; and he resided not in the sanctuary, but in one of the tents or apartments around it, assigned for the accommodation of the priests and Levites, his being near to that of the high priest.
the word of the Lord was precious in those days--It was very rarely known to the Israelites; and in point of fact only two prophets are mentioned as having appeared during the whole administration of the judges (Jdg 4:4; Jdg 6:8).
there was no open vision--no publicly recognized prophet whom the people could consult, and from whom they might learn the will of God. There must have been certain indubitable evidences by which a communication from heaven could be distinguished. Eli knew them, for he may have received them, though not so frequently as is implied in the idea of an "open vision."
1 Kings (1 Samuel) 3:3
sa1 3:3ere the lamp of God went out in the temple of the Lord--The "temple" seems to have become the established designation of the tabernacle, and the time indicated was towards the morning twilight, as the lamps were extinguished at sunrise (see Lev 6:12-13).
1 Kings (1 Samuel) 3:5
sa1 3:5he ran unto Eli, and said, Here am I; for thou calledst me--It is evident that his sleeping chamber was close to that of the aged high priest and that he was accustomed to be called during the night. The three successive calls addressed to the boy convinced Eli of the divine character of the speaker, and he therefore exhorted the child to give a reverential attention to the message. The burden of [the Lord's message] was an extraordinary premonition of the judgments that impended over Eli's house; and the aged priest, having drawn the painful secret from the child, exclaimed, "It is the Lord; let him do what seemeth him good." Such is the spirit of meek and unmurmuring submission in which we ought to receive the dispensations of God, however severe and afflictive. But, in order to form a right estimate of Eli's language and conduct on this occasion, we must consider the overwhelming accumulation of judgments denounced against his person, his sons, his descendants--his altar, and nation. With such a threatening prospect before him, his piety and meekness were wonderful. In his personal character he seems to have been a good man, but his sons' conduct was flagrantly bad; and though his misfortunes claim our sympathy, it is impossible to approve or defend the weak and unfaithful course which, in the retributive justice of God, brought these adversities upon him.