1 Samuel 3:5

And he ran unto Eli, and said here [am] I
He got out of his bed as fast as he could, and put on his clothes, and ran with all haste to the apartment where Eli lay, supposing he wanted some immediate assistance, which he was there ready to give him to the utmost of his ability; and he made the more haste, as knowing his age and infirmities, and being desirous, out of affection to him, to help him as soon as possible:

for thou calledst me;
he took it to be the voice of Eli, partly because there was no other man in the tabernacle, it being in the middle of the night, or early in the morning, before the doors were opened, or any of the priests were come in to minister, and partly because the voice might be very much like Eli's, and which was done to direct him to him:

and he said, I called not, lie down again;
he signified he wanted nothing, and so had no occasion to call him, nor had he, but bid him go to bed again, and sleep quietly:

and he went and lay down;
and very probably fell asleep again.