The lamp is a symbol for the Word of God,
"Thy word is a lamp unto my feet." (Psalm 119:105)
Samuel became a prophet, the light of God to His people.
Recommended Readings: 1 Kings 3:2-4
2 The people, however, were still sacrificing on the high places, because at that time a dwelling-place for the name of Yahweh had not yet been built.
3 Solomon loved Yahweh: he followed the precepts of his father David, except that he offered sacrifice and incense on the high places.
4 The king went to Gibeon to sacrifice there, since that was the principal high place -- Solomon presented a thousand burnt offerings on that altar.