What is the purpose of the eternal light in judaism?

Answer 1

It commemorates the Menorah (candelabrum) in the Holy Temple, and reminds us that God is present. See also:

More about Jewish synagogues and prayer

Answer 2

It is an oil lamp or electric light which is always kept burning, near the Holy Ark of the Torah scrolls. It symbolizes God's presence.

Answer 3

Light usually respresents wisdom, but it can also represent God's presence.

Answer 4

The Ner Tamid (נר תמיד) symbolizes God's eternal presence.

Answer 5

In the ancient Temple, there was an eternal light (in the form of a 7-branched menorah) in front of the Holy of Holies. The Torah merely commands, in Exodus 25:31-40, that it be there without really explaining why, but in effect, it became a symbol of God's presence. In synagogues, in memory of this, an eternal light is traditionally placed in front of or above the ark, the cabinet in the synagogue holding the Torah scrolls.